The nutrient-dense Protein Sparing Modified Fast (PSMF)

The Protein Sparing Modified Fast (PSMF) is regarded by many to be the most effective way to lose body fat while preserving muscle and avoiding rebound binge eating due to nutrient deficiencies.

First developed in the 1970s, the PSMF has seen various permutations in weight loss clinics and the bodybuilding community.

While the specifics vary depending on context, a PSMF generally defined as a diet with adequate protein, while simultaneously limiting energy from carbohydrates and fat.

While the protein intake is high in terms of the food on the plate, it could also be seen as a ketogenic diet due to the high contribution of body fat to your energy expenditure which will generate ketones.

Despite the peculiar name, there’s nothing really magical about a PSMF.  It just means that you pay particular attention to protein in an energy deficit.

If you want to lose weight quickly and body fat fast you need a more substantial deficit, and therefore more attention needs to be paid to ensuring you are getting adequate protein.

This article outlines the key principles of the PSMF that can be applied to weight loss or maintenance over the long-term.

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If you just want a PSMF calculator to determine your optimal protein, fat and carbohydrate range along with nutrient-dense foods and meals, then we recommend you get your Nutrient Optimiser free report.

Medical applications of the PSMF

In the medical version of the PSMF, patients obtain the majority of their energy from protein while keeping energy from carbohydrates and fat low.[1]

Protein levels are set at 1.2 to 1.5 g/kg of ideal body weight per day.  Note: For someone with 30% body fat wanting to get to 10% body fat this would be equivalent to 1.5 to 1.9g protein per kilogram of lean body mass or LBM.

  • Carbohydrate intake is typically restricted to less than 20 to 50 g/day.
  • Additional dietary fat beyond what comes with lean protein sources is minimised.
  • Patients in the weight loss clinic setting (e.g. for morbidly obese people in the lead up to bariatric surgery) are restricted to less than 800 kcal/day.

The Cleveland Clinic has carried out extensive research into the use of adequate protein low-calorie diets for aggressive weight loss and found that:[2][3][4]

  • patients are encouraged by the initial period of rapid weight loss which leads to a lower dropout rate;[5]
  • meal replacements in the form of commercial shakes or bars can be used, however learning to make meals from whole foods critical to developing habits that lay the foundation for long-term success;
  • the PSMF is effective for people with normal glycemic control as well as pre-diabetes or type 2 diabetes;[6]people on a whole food-based PSMF are significantly less hungry and preoccupied with eating compared to those on a liquid-formula based version of the PSMF; and
  • most of the weight lost during a PSMF is from fat tissue rather than muscle.[7]Adherence to a very-low-calorie, ketogenic PSMF program results in major short-term health benefits for obese patients with type 2 diabetes. These benefits include significant weight loss, often more than 18kg, within 6 months. 

In addition, significant improvements in fasting glucose and haemoglobin A1c levels are linked to the caloric and carbohydrate restriction of the PSMF.  Insulin resistance was also attenuated, with possible partial restoration of pancreatic beta-cell capacity.[8]

Bodybuilding applications

Lyle McDonald popularised the PSMF for the bodybuilding community in 2005 with his 2005 Rapid Fat Loss Handbook.

McDonald details how someone can individualise the PSMF based on their goals and context.

  • Someone who is already very lean and undertaking heavy weight training will need higher levels of protein, while someone who isn’t yet lean may do better with a less aggressive approach over a more extended period.
  • McDonald’s recommended protein intake ranges from 2.2 g/kg LBM to 4.4 g/kg LBM
  • Unlimited green leafy fibrous veggies are strongly encouraged as they are filling and provide the vitamins and minerals with minimal calories.
  • McDonald also recommends supplementing with a multivitamin, sodium potassium, magnesium, taurine, calcium and fish oil.
  • A severely energy restricted PSMF is typically not a long-term proposition due to the risk of nutrient deficiencies with a severe energy deficit.

If you are active and/or doing resistance training, then your requirement for protein is even higher.  As shown in the chart below from a recent review paper by Stuart Phillips, lean muscle mass is best preserved when we have at least 2.6g/kg total body weight where there is an aggressive deficit (e.g. 35%).  A lower protein intake of 1.5 g/kg body weight seems to be adequate where we have a more moderate deficit.

Protein drives satiety

The body fiercely defends loss of muscle mass by increasing appetite after periods of fasting or low protein consumption to ensure that muscle mass is retained.[10]

Conversely, as per the Protein Leverage Hypothesis (Simpson, 2005), it appears that we continue to eat until we get enough protein, and thus prioritising protein typically leads to a lower spontaneous calorie intake.[11][12]

“Protein generally increases satiety to a greater extent than carbohydrate or fat and may facilitate a reduction in energy consumption under ad libitum dietary conditions.”[13][14]

If we eat foods with a lower % of energy from protein we may end up consuming more energy to obtain our adequate protein.   Conversely, we can ‘hack’ our appetite by prioritising adequate protein while minimising energy from carbohydrate and fat.

The chart below shows the relationship between protein intake and energy intake based on half a million days of MyFitnessPal data, with the lowest spontaneous intake occurring with the highest protein intake (i.e. 2.4 g/kg LBM).

Similarly, the chart below shows that diets with a higher percentage of their energy from protein tend to increase satiety and lead to less energy intake while dietary approaches with less protein tend to increase spontaneous energy intake.

Protein is prioritised, with carbohydrates and fat viewed more as lower priority fuel sources:

  • Minimum carbohydrate requirement: While there is a need for the vitamins and minerals that are often packaged with carbohydrate-containing foods such as non-starchy vegetables, there is really no minimum level of carbohydrates.  While it takes a little bit more work, we can get the glucose we need for our brain function from protein via gluconeogenesis.
  • Minimum fat requirement: Most people have plenty of body fat stores that they can draw on and hence do not have an immediate need for dietary fat other than the essential Omega 3 fatty acids.  You can still get a robust micronutrient profile with 10% dietary fat (or 0.4 g/kg LBM).  This allows the fat from your body to be used for energy.

The secret to a sustainable and successful PSMF is to get adequate protein, along with vitamins, minerals, the essential fatty acids with energy.  This will improve satiety while also getting adequate nutrients which is really the holy grail of weight loss and long-term maintenance.

Thermic effect of food

The other advantage of consuming a higher protein diet is increased thermogenesis (i.e. the energy lost in the process of converting food into energy).  The thermic effect (or specific dynamic action) is 5 to 15% for carbohydrates and fat and 20 to 35% for protein.[15]The thermic effect of food is illustrated nicely by these images from Physioqonomics.[16]  We lose a lot more calories metabolising protein compared to fat or carbohydrates.

While there is much debate over the “metabolic advantage” of fat vs. carbohydrates with claims that we can eat more calories of fat than carbs, there is actually an advantage’ when it comes to how many calories of protein we eat versus how much we can convert to energy.

While we can convert protein to glucose (i.e. gluconeogenesis), it is harder to do, and our body doesn’t like to do unless it has to.[17] Satiety typically kicks in quickly once we have had adequate protein and we go in search of fat or carbs which are easier to convert to energy.

Just think, you can only eat so much steak, but you always have a ‘dessert stomach’, even after a big meal.  Humans are programmed to overeat foods with fat and carbs with minimal protein to ensure that they survive the coming winter.

Should you just eat the highest protein foods?

So, the obvious question is:

What should I eat on a PSMF?

The table below lists the foods with the highest protein content as a percentage of energy.  These foods may be useful if you are looking to boost your protein intake.

food % protein
cod 92%
haddock 92%
white fish 92%
crab 91%
lobster 91%
egg white 91%

For a  longer list of nutrient dense, high protein foods and meals tailored for your current situation and goals we recommend you get to obtain your Nutrient Optimiser free report.  Just select “fat loss (insulin sensitive)” as your goal.

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The problem with a very high protein diet

While you may be getting plenty of essential amino acids if you focus purely on high protein foods, you may not be getting all the vitamins and minerals you need.

As shown in the chart below, there is a strong relationship between protein and nutrient density.  However, if we only focus on high protein foods, we may still end up missing out on the harder to find vitamins and minerals.[18]

The chart below shows the micronutrients provided by the top 10% of the foods in the USDA database when sorted for maximum protein content.

Now imagine, that rather than getting 2000 calories, we are getting only 800 or 400 calories during long-term fasting or extreme dieting.  We have a higher chance of becoming deficient in many key nutrients which may in turn increase appetite and drive us to eat more than we would like to.

Ensuring you are getting adequate micronutrients is a key component to long-term success in weight loss and maintenance.  

In his Rapid Fat Loss Handbook McDonald mentions ‘The Last Chance Diet’ which was popular in the 1970s and 80s.  It was essentially a PSMF centred around liquid nutrition which led to the death of a number of devotees due to some fatal flaws.[19][20]First, they picked the cheapest protein source available, collagen; a protein that provides essentially zero nutrition to the body.  Second, they provided zero supplemental vitamins and minerals (some of which would have been obtained if the dieters had been eating whole foods in the first place). This caused a couple of problems including cardiac heart loss (from the total lack of protein) and arrhythmias from the lack of minerals.

Basically, the problem wasn’t with the approach so much as with the food choices.  PSMF’s based around whole foods (which provide high-quality proteins as well as vitamins and minerals) and with adequate mineral supplementation have shown no such problems.[21]

Bruce Ames’ Triage Theory

Nutrient density becomes even more critial when we consciously try to limit our energy intake.

Attaining adequate micronutrients can help to mitigate metabolic/mitochondrial slowdown and adaption to the severe calorie deficit.  If we are getting the range of micronutrients we need, the body is more likely to keep on feasting on our own fat stores without reacting like there is a famine.

Similar to the protein leverage hypothesis, it seems if we provide the body with low nutrient density food it is driven to consume more energy to ensure that it gets the nutrients it needs.

While we can argue that the some of the DRIs for various nutrients are overly conservative, you also don’t have to look too far to find people that argue that we need multiple times the DRI for another particular nutrient to optimise our health and longevity.

You don’t need to worry about precisely meeting the daily recommended intake for every single micronutrient every single day.  A healthy well-balanced diet will achieve the DRI for the majority of the essential micronutrients most of the time.

More research is required to understand whether our requirements for different nutrients change depending on our diet (e.g. how much less vitamin C do we need if we are not consuming as much glucose) and how much more bioavailable nutrients are from plants versus animals.

However, if you are an order of magnitude below the recommended values for a handful of nutrients, then you should consider focussing on foods that contain that contain higher levels of that cluster of nutrients.  If you are an order of magnitude over the recommended values for a particular group of nutrients you don’t need to prioritise foods that contain those nutrients.

Bruce Ames’ Triage Theory suggests that if we are low in critical nutrients, the body will prioritise those nutrients for functions essential to short-term survival rather than longevity and preventing the diseases of ageing (e.g. cancer, heart disease, Parkinson’s, Alzheimer’s, etc.).

“The triage theory posits that some functions of micronutrients (the approximately 40 essential vitamins, minerals, fatty acids, and amino acids) are restricted during shortage and that functions required for short-term survival take precedence over those that are less essential.  Insidious changes accumulate as a consequence of restriction, which increases the risk of diseases of ageing.”[22][23]

So, while we might do OK with poor nutrition for a period of time, we will probably do better if we obtain a substantial amount of all the essential nutrients.  Ideally, we would get these nutrients from whole foods which are more likely to contain all the non-essential but also beneficial vitamins and minerals that we don’t track.

The nutrient-dense adequate protein diet

So, to recap:

  1. getting adequate protein is essential, especially if we are fasting or restricting energy intake, and
  2. not getting sufficient nutrients is potentially dangerous and possibly the fatal flaw of the PSMF.

We can use the Nutrient Optimiser to prioritise foods with the nutrients we want to obtain more of.   Prioritising amino acids is usually unnecessary because maximising vitamins and minerals generally leads to more than adequate protein.   However, in a PSMF where we are severely limiting energy, we want to increase protein as well.

The chart below shows the resultant micronutrient profile achieved if we ate 2000 calories per day of the foods recommended by the Nutrient Optimiser.  When we focus on nutrient density, we get adequate quantities of all nutrients other than the Omega 3 fatty acid alpha-linolenic acid.

The chart below shows the same foods if we only ate 600 calories per day rather than 2000.  Even with these highly nutrient dense foods, we miss the DRI for eight of the essential nutrients.  Hence, we may still benefit from supplementing with Omega 3, vitamin D, calcium, magnesium and potassium if we are intentionally limiting energy on a PSMF.

It’s not hard to imagine that our ability to maintain a low energy intake and achieve sustained weight loss is likely related to getting adequate levels of the various essential micronutrients without having to over-consume energy.  Conversely, a nutrient-poor diet will likely drive us to consume excess energy which will lead to obesity.

Calorie math

To make this a little more practical let’s look at some calorie math using a hypothetical scenario.  If you want to skip the numbers and are looking for a PSMF calculator, then we recommend you check out the Nutrient Optimiser free report and select fat loss (insulin sensitive).

Let’s say Super Ted is looking to get shredded for the Ketogains conference in two weeks but also wants to stay strong and to win the arm wrestle and beat the reigning champion, Mighty Mouse.

Super Ted currently weighs 160 lbs or 73kg and has 10% body fat.  His maintenance energy intake is 2336 cal/per day.

While getting the majority of your dietary energy from protein might seem excessive…

… it’s not so dramatic when you also take into account the body fat being burned.

Between the 8% dietary fat (8%) his body fat stores (60%) Super Ted will be getting a ketogenic level of 68% of his energy from fat while also adequate protein to maintain his muscles and enough carb containing vegetables to get the vitamins and minerals that are also critical to his long-term success.

The details of the calorie math are shown below.  Once you take the energy deficit into account Super Ted is consuming 2.2g/kg LBM.

body weight (kg) 73
body weight (lbs) 160
body fat (%) 10%
lean body mass (kg) 62
maintenance (cal) 2336
deficit 60%
diet (calories) 934
protein (% diet) 59%
fat (% diet) 20%
net carbs (% diet) 13%
diet protein (g) 138
dietary fat (g) 21
body fat (g) 156
body fat (kg/week) 1.1
net carbs (g) 30
fibre (g) 19
protein (% energy burned) 24%
dietary fat (% energy burned) 8%
carbohydrate (% energy burned) 5%
protein (g/kg LBM) 2.2

When you look at his Nutrient Optimiser analysis, you see that Ted Naiman (aka Super Ted) is actually consuming 2.4g/kg LBM.

Meanwhile, Luis Villasenor (aka Mighty Mouse) is also consuming protein at 2.4g/kg LBM during his PSMF.  Luis says his regular protein intake is around 140g increases this up to 180g during a strict PSMF.

Insulin resistant long-term fat loss scenario

For most of us, such an aggressive fat loss approach might be hard to maintain long-term.  So, let’s consider another scenario with another hypothetical character.

Introducing…  Big Ted.

Big Ted doesn’t post shirtless for photos on the internet.

At 110kg and 30% body fat Big Ted is far from shredded.

Big Ted is also pre-diabetic.

His doctor has warned him that if he doesn’t lose a significant amount of weight he will need to take Metformin and then insulin before too long.

Big Ted is motivated to drop a significant amount of weight with perhaps a calorie deficit of 30% which will take him about 30 weeks to get to his goal weight of 90kg.

We can refine Big Ted’s PSMF approach given that his circumstances and goals are different from Super Ted’s.  Rather than just prioritising nutrient density and energy density, this scenario also prioritises a lower insulin load given Big Ted’s looming pre-diabetes situation.

The chart below shows the nutrient profile of these foods once we take a 30% energy deficit into account.  Big Ted will be meeting the DRI for all his nutrient other than Omega 3s which he may need to supplement.

This is basically a hybrid between a PSMF and a low carb diet.  If you want to try this approach in the Nutrient Optimiser select ‘fat loss (insulin resistant)’ for a not so aggressive version of the PSMF for a lower long-term approach.

Calorie math

The charts below show the energy consumed and energy burned.  There is a significant amount of fibre which will not be metabolised for energy, but rather feed his gut bacteria.  There is still a substantial amount of net carbs from veggies. However, there are no sugars or processed grains to be seen, so they’re not about to boost his insulin or send him on a blood sugar roller coaster.

Once his body fat loss is accounted for, half of Big Ted’s energy expenditure is still coming from fat.

Although we didn’t prioritise amino acids, we still get a solid 2.2g/kg LBM protein.

body weight (kg) 110
body weight (lbs) 242
body fat (%) 30%
lean body mass (kg) 77
maintenance (cal) 3000
deficit 30%
diet (cals) 1875
protein (% diet) 36%
fat (% diet) 30%
net carbs (% diet) 20%
fibre (%) 14%
diet protein (g) 169
dietary fat (g) 63
body fat (g) 100
body fat (kg/week) 0.7
net carbs (g) 94
fibre (g) 66
protein 23%
dietary fat 19%
carbohydrate 13%
protein (g/kg LBM) 2.2

As shown below, the nutrient profile of these foods is also excellent.  These foods will help Big Ted to minimise his chance of developing nutrient deficiencies which may lead to rebound binge eating and derail his long-term weight loss efforts.

How often should I eat on a PSMF?

Big Ted is fond of intermittent fasting.  He finds it easier to not eat for a day or two and then eat to satiety rather than trying to count calories or restrict energy.  Meanwhile, Super Ted likes to eat two meals per day which save him time and helps him not overeat.  But which one is ideal?

It’s not so important when you eat as long as you stick to the foods that align best with your goals.  Recent research suggests that in the fasted state we can use up to 3.5 g/kg/day and digest up to 4.3 g/kg/day of protein.[25]  This makes sense in an evolutionary context when there wouldn’t have been a regular supply of food, but we would have needed to be able to use the food when we came across a big hunt after a long famine.

Practically though, it can be hard to consume your minimum protein allocation in one sitting.  Eating two meals a day seems to be ideal to help you maintain a consistent deficit while maximising satiety and minimise your opportunities to continue to eat.

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Eating earlier in the day also appears to be better as it aligns better with your circadian rhythm and insulin sensitivity as well as eliminating opportunities to overeat which seems to be easier at night when you have time to kill rather than when you are trying to get on with your day.

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How low can you go?

A PSMF is never a zero calorie fast as it will have enough calories to get the protein you need and ideally some essential fats and adequate vitamins and minerals.  People with more fat to loss will be able to maintain a more significant deficit for longer without losing muscle than lean bodybuilders.  Your Nutrient Optimiser free report will give you an estimate of this lower calorie intake based on your current body fat levels, and your minimum recommended protein intake.

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Each person needs to find the ideal approach that they can sustain until they achieve their goal.

Ideally, if you’re going to the effort of tracking your food and dieting, then you want to be losing at least 0.5% body weight per week.   If you’re not achieving at least 0.5% per week, you should ratchet down your maximum calorie intake until you do.

Weight loss of 1.0% per week should be treated as an upper limit over a shorter period.  If you’re losing more than 1.0% per week over the long term you may risk losing excessive amounts of lean muscle mass.

What about rabbit starvation

Rabbit starvation happens to very lean people if they only have lean protein foods with minimum fat available.  They just can’t get enough energy to sustain high levels of body fat.  However, for most of us who have plenty of body fat, this is an advantage.

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How to do a nutrient dense PSMF

  • Eat more of the foods and meals recommended your Nutrient Optimiser free report.  
    • The fat loss (insulin sensitive) option is designed for aggressive short-term weight loss (i.e. leading up to a bodybuilding comp).
    • The fat loss (insulin resistant) option may be more appropriate if you have more weight to lose over a more extended period.
    • Minimum protein intake in a weight loss clinic setting is 1.2g/kg total body weight.  Your appetite will likely drive you to eat more protein if you are working out.   2.2 to 2.4 g/kg lean body mass is typical for someone lifting heavy.
    • Focusing on nutrient-dense foods will ensure you still get adequate protein as well as vitamins and minerals while minimising energy consumption.
    • Eat only carbs that come with non-starchy veggies (i.e. no processed grains or foods with added sugars).  Eat only the fat that comes with lean protein foods.
  • Don’t eat too much
    • It will be hard to overeat these high nutrient density low energy density foods.
    • It may be beneficial to track or plan your energy intake to ensure you are achieving your goals.
    • Ratchet down your maximum energy intake until you achieve your desired rate of weight loss (e.g. greater than 0.5% per week).
  • Lift heavy / exercise (optional)
    • If you are dieting and not active the body will see your muscle as unnecessary and expensive.  Resistance training will help you to use the protein to build lean muscle and keep your metabolic rate up.
  • Pay attention to your micronutrients
    • To improve your chance of long-term success, it’s essential to pay attention to both your protein and your micronutrient intake.    If you want to maximise your chance of success you can track your food in Cronometer and feed it back into your Nutrient Optimiser report to determine the optimal foods and meals to help you continue to fill your nutrient gaps.

Summary

  • The protein sparing modified fast (PSMF) provides adequate levels of protein to support lean muscle mass while restricting energy from carbohydrates and fat.
  • Protein intakes vary widely depending on the goals and the level of energy restriction between.
  • Providing adequate nutrients, ideally from whole foods, is critical to long-term weight loss and maintenance.
  • It is crucial to prioritise nutrient-dense foods to improve your chances of long-term success.
  • While the PSMF is commonly used in weight loss clinics and the bodybuilding community, the principle can also be applied in other situations to maximise fat loss while maintaining lean muscle mass.

 

References

[1]http://www.mdedge.com/ccjm/article/96116/diabetes/protein-sparing-modified-fast-obese-patients-type-2-diabetes-what-expect

[2]https://www.ncbi.nlm.nih.gov/pubmed/9149474

[3]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784653/ama

[4]https://www.ncbi.nlm.nih.gov/pubmed/4037162

[5]http://www.mdedge.com/ccjm/article/96116/diabetes/protein-sparing-modified-fast-obese-patients-type-2-diabetes-what-expect

[6]https://www.ncbi.nlm.nih.gov/pubmed/24513578

[7]http://www.mdedge.com/ccjm/article/96116/diabetes/protein-sparing-modified-fast-obese-patients-type-2-diabetes-what-expect

[8]https://www.dropbox.com/s/rjfyvfsovbg9fri/The%20protein-sparing%20modified%20fast%20for%20obese%20patients%20with%20type%202%20diabetes%20What%20to%20expect.pdf?dl=0

[9]http://www.mdedge.com/ccjm/article/96116/diabetes/protein-sparing-modified-fast-obese-patients-type-2-diabetes-what-expect

[10]http://www.nature.com/ejcn/journal/v71/n3/full/ejcn2016256a.html

[11]http://onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2005.00178.x/abstract

[12]https://www.dropbox.com/s/zej4razn4dn993y/protein%20leverage%20hypothesis%20-%20simpson2005.pdf?dl=0

[13]http://ajcn.nutrition.org/content/87/5/1558S.long

[14]https://www.ncbi.nlm.nih.gov/pubmed/15466943

[15]https://en.wikipedia.org/wiki/Specific_dynamic_action

[16]http://physiqonomics.com/calories-child-friendly-version/

[17]http://www.biologydiscussion.com/biochemistry/energy-production/specific-dynamic-action-factors-and-example-energy-production/43998

[18]https://optimisingnutrition.com/2017/05/27/is-there-a-relationship-between-macronutrients-and-diet-quality/

[19]http://www.dietsinreview.com/diets/last-chance-diet/

[20]https://www.amazon.com/Last-Chance-Diet-When-Everything-Failed/dp/0818402393

[21]http://www.bodyrecomposition.com/the-rapid-fat-loss-handbook/

[22]https://www.ncbi.nlm.nih.gov/pubmed/19692494

[23]http://ajcn.nutrition.org/content/90/4/889.full.pdf+html

[24]https://optimisingnutrition.com/2017/05/27/is-there-a-relationship-between-macronutrients-and-diet-quality/

[25]http://www.sciencedirect.com/science/article/pii/S0261561417302030

post updated August 2017

how much protein is too much?

Now that fat is out of the spotlight, the focus for many in low carb and vegan circles has turned to protein as the macronutrient that needs to be avoided for health, good blood sugar control and longevity.

At the same time there are still are plenty of ‘meat heads’ who say that their ‘brotein’ can do no wrong and you can’t get enough of it.

In the sea of conflicting opinions and advice, how do we determine the optimal amount of protein that will suit our situation, goals and needs?

How much protein do we need?

How much is too little protein?

How much protein is too much?

This is an intriguing, controversial and multifaceted discussion.

So hold on as I try to unpack the various perspectives!

Typical guidance

First, let’s look at the general recommendations for protein intake.

Lean body mass

Protein recommendations are often given in terms of grams per kilogram of lean body (LBM) where “LBM” is your current weight minus your fat mass.

Protein is required to support your muscles, not your fat.

You can use a DEXA scan, bioimpedance scale or pictures (like the ones below) to estimate your level of body fat (% BF) and then calculate your LBM using the following formula:

lean body mass (LBM) = body weight weight x (100% – %BF) / 100%. 

None of these methods are particularly accurate.  However, calculating your body fat levels or protein intake to a high degree of accuracy is not necessary for most people.

Absolute minimum protein requirement

According to Cahill’s starvation studies[1] we burn around 0.4g/kg LBM per day of protein via gluconeogenesis during long term starvation.

After we burn through the food in our stomach and then the glycogen stored in our liver and muscle, the body will turn to its own internal protein stores (i.e. muscles, organs etc) and, to a lesser extent, fat (glycerol backbone) to obtain glucose via gluconeogenesis.

The figure below shows that we use less protein the longer we go without food.  After a couple of days of no food, fat and ketones kick in to supply the energy deficit.

People with better insulin sensitivity may burn through less protein as they are able to access their body fat stores for energy more easily when they go without food.  However, people who are lean and insulin sensitive may have less body fat to burn before the body will turn to protein during fasting.  Hence, extended fasting is not typically recommended if you are super lean.

Gluconeogenesis peaks at around two days and decreases thereafter as insulin levels decrease  and ketones rise further.  While chronic muscle loss is bad news (sarcopenia), particularly in old age, short term gluconeogenesis and autophagy is not necessarily a bad thing as the body will ‘self eat’ and clean out the old and sick and superfluous parts of the body for fuel.

After a fast the body is primed and highly insulin sensitive and ready to build new muscle.   Fasting can actually be beneficial for gaining muscle provided that the refeed has adequate amounts of amino acids to support muscle growth.

Daily recommended protein intake

The Daily Recommended Intake (DRI) for protein is 0.84g/kg of body weight (BW) while the Estimated Average Requirement (EAR) is 0.68 g/kg BW.[2]

This minimum protein level is based on nitrogen balance studies that indicate that if healthy test subjects eat less than around 0.6 g/kg BW you will be losing muscle and be at risk of the various diseases of malnutrition and then factored up to 0.8 g/kg BW as a factor of safety.[3] [4] [5] [6] [7]

Keep in mind though that the DRI is a recommended minimum per day to prevent diseases related to protein deficiency.  This is not necessarily optimal.

More recent studies have indicated that higher quantities of protein may be necessary, particularly for older people.[8] [9] [10] [11] [12] [13]

Older people appear to require 1.0 to 1.3 g per kilogram of total body mass per day protein to optimize physical function, particularly whilst undertaking resistance exercise recommendations.[14]

As discussed in the article Is there any relationship between macronutrients and diet quality (micronutrients) it’s actually quite hard to achieve adequate levels of vitamins and minerals while also hitting these minimum DRI levels.

According to Simpson and Raubenheimer in Obesity: the protein leverage hypothesis (2005) people with diabetes may actually need to eat more protein to ensure that they have adequate levels to build lean muscle mass given that gluconeogenesis can be higher due to insulin resistance.

Keep in mind too that minimum protein recommendations are given in terms of total bodyweight, not lean body mass.  For someone with 30% body fat 0.8g/kg BW will convert to 1.1 g/kg LBM.

If you fast for a day or two you should consider compensating with more protein on your feasting days.  If you are fasting for fat loss there is no need to replace additional fat when you feast.

DRI for individual amino acids

If we dig a little deeper we see that there are also requirements for individual amino acids as shown in the table below.[15] [16]  Depending on what you’re eating you can be deficient in some amino acids while getting enough other amino acids.

 

Amino acid(s) mg per kg body weight mg per 70 kg mg per 100 kg
Histidine 10 700 1000
Isoleucine 20 1400 2000
Leucine 39 2730 3900
Lysine 30 2100 3000
Methionine Cysteine 10.4 + 4.1 (15 total) 1050 1500
Phenylalanine + Tyrosine 25 (total) 1750 2500
Threonine 15 1050 1500
Tryptophan 4 280 400
Valine 26 1820 2600

The Nutrient Optimiser reviews the individual amino acids to make sure they are all adequate.     People who are running close to the minimum DRI for protein overall are typically deficient in a handful of individual aminos.

cropped-2017-04-22-2

Typical protein intake

The average protein intake for the general western population is about 1.2 g/kg LBM or around 16% of calories.[17]  This is greater than the minimum required to maintain nitrogen balance in the figure above and the DRI values.

It seems that most people get enough protein without trying too hard.   However, what constitutes as “enough” protein will vary depending on whether you are going through puberty, weight lifting,a middle aged sedentary office worker or an elderly person in a nursing home.

Appetite is a strong drive that ensures that you don’t stop eating until you get enough protein.  Average protein intake seems to be consistent across cultures and time.[18]

Practical maximum protein intake

Recent research indicates that, when fasted, we can use up to 3.5g/kg/day and breakdown and metabolise up to 4.3g/kg/day.[19]  This makes sense in an evolutionary context where would be primed to use a lot of protein after going without and then making up for lost time after a successful hunt.

Rabbit starvation’ is said to occur when people only have lean protein available and just can’t get enough calories in because they are eating only lean protein.  However, I have seen people eat higher levels of protein in an energy excess situation when they are trying to gain weight (e.g. Andy Mant who is trying to gain size eating and muscle 4.4g/kg LBM or Bailan Jones who is a growing young man with type 1 diabetes at 5.0g/kg LBM).

From a pure calorie standpoint we could theoretically eat up to around 7g/kg LBM using very protein foods.   However, most people will struggle to eat more than 3.5g/kg LBM because protein is very satiating and it is hard to find protein containing foods that don’t come with substantial amounts of fat.

The chart below shows the nutrient score for the highest protein 10% of the foods in the USDA database.  What we can see is that high protein foods provide a ton of amino acids while lacking key vitamins and minerals.  This is not an optimally balanced diet at a micronutrient level.  Rather than worrying specifically about ‘too much protein’ I think it’s more useful to think in terms of getting the range of micronutrients you need without having to consume excess energy.

I think the real problem eating ‘too much protein’ is that once our protein goes too high we end up reducing the amount of vitamins, minerals and essential fatty acids that our food contains.  While it is important to get adequate amino acids, it is also important to get adequate vitamins, minerals and essential fatty acids.

It’s also worth keeping in mind that protein has a net acidic load that the body needs to balance to maintain acid/base homeostasis.  If we eat a lot of protein without adequate amount of alkalising minerals (e.g. potassium, magnesium, phosphorus and calcium) our kidney may struggle to maintain an optimal pH balance which can lead to low level metabolic acidosis in the long term.[20] [21]

How will you spend your “discretionary calories”?

I think it’s important to keep in mind that the DRIs for protein are a minimum to prevent disease and should not be treated as optimal targets or maximum values.  Finding the right balance of all the essential nutrients is quite a balancing act.

In this video Dr Donald Layman points out that if we targeted the minimum DRI for protein, carbs and fat we would end up with only eight hundred calories per day whereas, on average, we eat around 2300 calories per day.  Hence, there is a window of “discretionary calories” that we can chose how we fill to make up our daily energy requirements.

People in low carb circles are fond of saying ‘there is no such thing as an essential carbohydrate’.  So, once we cut the carbs out we are left with only 314 calories to meet our essential macronutrient requirements as shown in the table below.

macro DRI (g) DRI (calories) % energy
minimum protein 56 224 71%
Essential fats 10 90 29%
total 66 314 100%

Now this might be reasonable if we were minimising calories for weight loss (e.g. we could try to live on protein powder and Omega 3 capsules).  However, this this would be impossible to achieve with whole food.

Discretionary calories from body fat

The chart below shows the break up of energy sources if we were living on the minimum DRI for protein and essential fatty acids.  85% of our energy would be coming from our body fat stores.  This would be the ultimate protein sparing modified fast (PSMF) however there is a pretty good chance we would struggle to obtain adequate levels of vitamins and minerals from 300 calories.

Then once we reached our goal weight we would need to work out what we are going to fill the rest of our intake with to prevent drastic weight loss (and literally starving to death)?

From carbs

Another option is to fill the window of ‘discretionary calories’ with carbohydrates which would look like this.

macro DRI (g) DRI (cals) % energy
protein 56 224 10%
carbs 497 1986 86%
fats 10 90 4%
total 563 2300 100%

From protein

Filling your energy deficit with protein would be impossible in terms of available foods (even with protein powders which are only 80% protein) as well as the strong satiety that would kick in well before then.

macro DRI (g) DRI (cals) % energy
protein 545 2181 91%
carbs 7 29 5%
fats 10 90 4%
total 250 2300 100%

From fat

The other option is to fill the remaining energy deficit with dietary fat.  This looks like a therapeutic ketogenic macro ratios.  This will be difficult without consuming the majority of your energy intake from butter, cream and MCT oil.

macro DRI (g) DRI (cals) % energy
protein 56 224 10%
carbs 7 29 5%
fats 227 2047 85%
total 291 2300 100%

Optimising for micronutrients and insulin load

My suggestion is to look to fill your remaining energy requirements with foods that provide the micronutrients you need while keeping an eye on the insulin load of your diet.

Keeping your blood sugar and insulin levels down will help normalise appetite and access your own fat stores for fuel.

However, ensuring that you are getting the micronutrients you need will help you prevent nutrient cravings with less energy which will be ideal for optimising longevity, insulin resistance and blood sugar levels.

How much protein are real people actually eating?

Protein in real life varies significantly, as evidenced by the fifty or so people on whom I have run the Nutrient Optimiser analysis.   As you can see in the table below, protein intake in real life is highly variable.  The average protein intake amongst these people who are generally following a low carb diet is 2.1g/kg LBM.

Name score protein (g/kg LBM) protein (%) fat (%) fibre (%) net carbs (%)
Rhonda Patrick 82% 2.5 17% 57% 10% 15%
Briana Theroux-Hulsey 79% 3.5 29% 21% 15% 35%
David Houghton 77% 0.6 17% 2% 21% 60%
Andy Mant v3 77% 4.4 27% 53% 5% 15%
Alber Van Zyl 75% 1 15% 77% 2% 6%
Alma Fuente 75% 5.3 27% 60% 7% 6%
Mike Berta 74% 2.1 31% 58% 4% 7%
Alex Leaf 74% 3.3 33% 26% 10% 32%
Alex Ferrari 74% 2 17% 54% 6% 24%
Deb Pinsky Lambert v2 72% 1.2 31% 61% 3% 6%
Luis Villasenor 72% 2.4 43% 48% 3% 5%
Gayle Louise 71% 2.4 40% 49% 4% 7%
Ted Naiman 70% 2.4 24% 64% 5% 7%
Andy Mant v2 70% 3 26% 54% 6% 15%
Robin Reyes v3 69% 1.6 18% 67% 6% 8%
Ruth Jamieson v2 66% 1.6 18% 67% 6% 8%
Amy 65% 3.3 41% 57% 0 1%
Paul Burgess 64% 1.9 28% 46% 6% 19%
Chris Hobson 63% 2.3 27% 63% 3% 8%
Ingunn Lovik 62% 1.5 21% 70% 1% 8%
Sophia Thom 62% 1.1 24% 65% 4% 7%
James DiNicolantonio 62% 3.3 26% 53% 5% 16%
Franziska Spritzler 61% 2.3 27% 55% 10% 8%
Sarah Koenck 58% 2.2 14% 77% 4% 6%
Ruth Jamieson v1 57% 1.4 19% 65% 7% 9%
Maria Fornarciari 52% 1.6 30% 61% 3% 6%
Matija Mlakar 50% 2.1 23% 49% 11% 17%
Nicole Jacobi 48% 2.8 32% 60% 3% 6%
Graeme Monteith 48% 2.6 18% 67% 5% 10%
Dave Knowles 46% 2.4 31% 63% 2% 3%
John Robertson 46% 1.4 16% 59% 4% 21%
Leah Williamson 44% 1.8 19% 75% 2% 3%
Nicole Ricine 43% 2.1 18% 79% 1% 2%
Balin Jones 43% 5 26% 66% 3% 5%
Kevin Tunis 37% 1.2 17% 76%% 1%% 7%%
Andy Mant v1 34% 3.7 35% 54% 2% 9%
George 34% 0.8 9% 69% 9% 12%
Robin Reyes v2 32% 1.6 21% 59% 4% 15%
Lorraine Ayre 30% 1.3 19% 64% 5% 12%
Terry Palmer 29% 1.5 25% 62% 5% 8%
Paul Stansel 28% 1.5 18% 77% 2% 3%
Gigi Giodani 26% 1.6 15% 81% 1% 2%
John Kerr 25% 0.7 11% 84% 2% 3%
Robin Reyes v1 23% 1.1 13% 50% 2% 35%
Bacon Man 22% 2.6 30% 69% 0% 1%
Patrick Butts v1 21% 0.8 18% 73% 4% 5%
Patrick Butts v2 20% 1.4 26% 66% 3% 6%
Harry Nguyen 20% 2.3 20% 72% 4% 4%
average 53% 2.1 24% 60% 5% 11%
25th percentile 34% 1.4 18% 54% 3% 6%
75th percentile 70% 2.5 28% 68% 6% 15%

I have also included the 25th and 75th percentiles, which indicate that half of these people were eating between:

  • 1.4 and 2.5g/kg LBM protein per day,
  • 18 and 29% energy from protein,
  • 54 and 67% energy from fat, and
  • 6 and 15% energy from net carbs.

Very few of these people are consuming anywhere near the minimum DRI levels for protein.  And the people who are the closest have some of the poorest nutrient scores.

Protein scales with activity levels

Unfortunately, simply eating protein doesn’t build muscles.  You also need to exercise to use the protein to build lean body mass (i.e. muscles).  If you’re active, you’ll need more protein for growth and repair of muscles.  If you’re sedentary you’ll need less.

There appears to be an upper limit to how much protein can be used for muscle protein synthesis (i.e. to grow and repair your muscles).  If you’re active, then it’s likely that your appetite for protein will increase to make sure you get these higher levels of protein to prevent muscle loss.

As shown in the figure below from Effects of Exercise on Dietary Protein Requirements (Lemon, 1999):[22] [23]

  • a strength athlete won’t stimulate more muscle protein synthesis by eating more than about 1.8 g/kg LBM;
  • an endurance athlete won’t trigger more muscle protein synthesis with more than around 1.4 g/kg LBM; and
  • someone who is sedentary won’t trigger more muscle protein synthesis with more than around 0.9 g/kg LBM.

So, if you are wanting to minimise energy intake while still building muscle you could use these values as a minimum protein intake.

is protein really a good source of energy?

We typically think in terms of the macronutrients, carbs, fat and protein as if they are all sources of energy.  However, there are some that argue that protein should not be considered be an energy source equivalent to carbs and fat.

Protein is critical for growth and repair of our muscles and organs and our neurotransmitters.[24]  While it is true that protein can be converted to glucose and ketones if required, the reality is that it is not easy for the body to do this![25]

The amount of energy lost in processing each macronutrient (i.e. the thermic effect of food or specific dynamic action) is shown in the table below.[26]  Compared to carbohydrate and fat, it takes a lot of energy to convert protein to glucose.  The body just doesn’t want to do it unless there is absolutely is no glucose available from any other sources.

macronutrient min max
carbohydrate 5% 15%
Protein 20% 35%
fat 5% 15%

Personally, I find that if I eat a lot of protein and not much else my appetite for carbs or fat will increase.  It seems that my body wants to use anything other than protein to replenish liver glycogen.  To quote Jason Fung:[27]

Why would your body store excess energy as fat, if it meant to burn protein as soon as the chips were down? Protein is functional tissue and has many purposes other than energy storage, whereas fat is specialised for energy storage.

Would it not make sense that you would use fat for energy instead of protein?  Why would we think Mother Nature is some kind of crazy? 

That is kind of like storing firewood for heat. But as soon as you need heat, you chop up your sofa and throw it into the fire. That is completely idiotic and that is not the way our bodies are designed to work.

oxidative priority

There is only a small capacity for protein storage in our blood stream and we waste around 25% of the energy from the protein as heat in processing it.  Hence, the body typically doesn’t drive us to overeat protein, but it can be used for fuel if there is nothing else to burn.   It makes sense that protein sends a strong satiety signal back to our brain once we have eaten as much as we can use.

It’s also useful to look at protein in terms of oxidative priority.  Craig Emmerich from mariamindbodyhealth.com has prepared the below refinement of Ray Cronise’s oxidative priority chart[28] (see Oxidative Priority, Meal Frequency, and the Energy Economy of Food and Activity: Implications for Longevity, Obesity, and Cardiometabolic Disease) by adding in ketones.

What this means is:

  1. The body will prioritise clearance of alcohol because there is no storage system for it.
  2. Similarly, the body will look to clear ketones from the system because there is minimal storage capacity for them in the blood.
  3. The body will look to clear protein that hasn’t been used for muscle repair and neurotransmitters for brain function.
  4. We will turn to glucose, for which we have a greater storage capacity in our liver, muscles and bloodstream.
  5. Lastly, once we have burned through all these other substrates, will we look to burn our fat, either dietary or the fat stored on our body.

So, if you want to burn body fat you need to limit alcohol, exogenous ketones, protein, carbohydrate and dietary fat.

Oxidative priority versus insulin load

I think Cronise’s oxidative priority concept is another way to look at the insulin load of our diet.

insulin load = carbohydrates – fibre + 0.56 * protein

Our body uses insulin to keep glycogen stored in our liver and fat in our adipose cells until the other fuels are used up.  There is no point in going out of our way to consume excessive protein because it takes more effort to burn through before we can get to the fat on our plate or our belly.   However, it is logical that our appetite switches off once we get enough protein because there is no room to store excess protein and it’s hard work to burn it.

but what about mTOR?

mTOR (mammalian target of rapamycin) controls our fuel flow and our appetite.  Similar to insulin and insulin-like growth factor (IGF-1), mTOR promotes growth.  Growth is good if we are a baby or a teenager.  But some people grow too much.

There is a limited number of times we can turn over our cells in our lifetime.  Constant periods of plenty without periods of restriction leads to continued growth of unwanted things like cancer.

Dr Ron Rosedale is a proponent of limiting protein in an effort to extend lifespan.

There have been a number of other proponents of limitation of animal protein in the vegan circle for some time. Dr Greger’s Plant Based NutritionFacts.org recommends limitation of methionine, leucine and isoleucine.

Dr Steven Gundry recommends a grain free high fat version of the protein restricted approach.

One option in response to this theory is to consistently restrict protein to achieve long term health.  Some people try to keep their protein low to ensure that they are always in a state of autophagy or muscle breakdown and self eating.

However, I don’t think chronic intentional protein restriction is necessarily optimal.  What we are aiming for is adequate, but not excessive, energy intake (including protein) without malnutrition (i.e. vitamins, minerals, aminos and essential fatty acids).

On top of this, balanced periods of feasting and fasting will allow autophagy and growth.

Before we had refrigerators

In the days before agriculture, fertilisers from fossil fuels, and even refrigerators in our homes (less than 100 years ago) our environment would enforce periods of growth and period of famine.

These days, we can source cheap food to keep on growing 24/7, 365 days a year.   We have no externally enforced periods of autophagy when we can clear the old and dying proteins in our body.

If we have growth interspersed with fasting, then we give the body a chance to build muscle and use protein for repair while also giving the body a chance to clean house and purge the dying white blood cells and burgeoning cancer cells before it gets ugly.

Your body will naturally crave more protein in periods of activity and repair and less in periods of inactivity.  If your appetite isn’t working as well as you’d like it to (i.e. you have more body fat than you would like), you can force a feast / fast cycle based on managing your weight or your blood glucose levels.

Like many things in life, optimal protein intake is a balance between extremes.  More is not necessarily better.  But less is not better either.  We want our body to thrive on enough, but not too much energy while still getting the micronutrients it needs.

Too much mTOR and IGF-1 can stimulate excessive growth and cancer while too little can lead to muscle loss, which does not support health in old age.[29]   The EAR and DRI for protein actually increase for people over 70 to prevent sarcopenia.  If you are lacking lean muscle mass then there is a greater chance you will not have great insulin sensitivity in old age.

If you are suffering from sarcopenia you may fall and break your hip and never get up again.  As shown in the figure below, too much or too little IGF-1 is not good.  As with most things, it’s a balance.

protein leverage hypothesis

Protein is critical to life so our appetite typically makes sure we get enough.  “Obesity: The protein leverage hypothesis[30] suggests that we keep eating until we get enough protein.  If we are getting plenty of protein then we will stop eating when we get enough energy and protein.

In the wild, animals have an innate sense of the nutrients they need and which foods will provide those requirements, whether they be protein, energy or other micronutrients.

While it’s easy to track macronutrients and calories, I think it’s often the body’s micronutrient needs that derail our calorie restriction efforts and aspirations.

Most of the food that is available to us these days is much more deficient in micronutrients than it once was, but at the same time it is flavoured and coloured to make it appear that it has heaps more nutrition than it actually does; so we keep on eating the food that is manufactured to look and taste good, all the while not getting the micronutrients we really need from the food, so we just keep eating.

We need a range of nutrients from our food to fuel our mitochondria so that it can efficiently burn through the food we eat, and not have it sit around in the blood.[31] [32]

For instance, the figure below from Spectracell shows the nutrients that are often missing in people with diabetes.[33]  We need all these nutrients from our food to support our mitochondria to effectively produce energy from our food and stop excess glucose and fatty, fatty acids and ketones building up in our blood stream.

action steps

It’s important to meet your minimum protein intake which may be higher if you are growing, older or active.

Once you’ve met the minimum intake of protein and essential fatty acids (about 314 calories per day) you need to decide what you are going to fill the rest of your “discretionary calories” with to prevent starvation.

If you are looking for therapeutic ketosis (i.e. for cancer, epilepsy, dementia, Alzheimer’s etc) then you may want to get the majority of your energy from fat while maintaining minimum protein levels and also staying in an energy deficit (see optimal foods for therapeutic ketosis).[34] [35]

If you’re managing diabetes and not looking to lose weight you will likely want to keep your carbohydrates low and get more of your energy from fat (see optimal foods for diabetes and nutritional ketosis).

If you’re wanting to lose body fat then perhaps you can count the energy from your body as part of your daily intake and try to maximise the nutrient density of the remaining intake.  That is, maximise nutrients with the minimum amount of energy intake (see optimal foods for fat loss).

summary

  • You can get too much protein but at the same time you can get too little protein.
  • Periods of feasting and fasting are beneficial rather than targeting chronic high or low protein.
  • It’s very hard to get a good balance of micronutrients with low protein. Protein tends to come packaged with other nutrients.
  • If you focus on micronutrients (vitamins, minerals, amino acids, fatty acids) then the macronutrients (carbs, fat and protein) largely look after themselves. We will get enough, but not excessive, amounts of protein.

 

references

[1] http://www.nejm.org/doi/full/10.1056/NEJM197003192821209

[2] https://www.nrv.gov.au/nutrients/protein

[3] http://ajcn.nutrition.org/content/77/1/109.full

[4] https://www.ketogenicforums.com/t/hobbit-vs-2-keto-dudes/10641/12

[5] http://www.ketogenic-diet-resource.com/daily-protein-requirement.html

[6] https://intensivedietarymanagement.com/how-much-protein-is-excessive/

[7] http://perfecthealthdiet.com/category/nutrients/protein/

[8] https://www.ncbi.nlm.nih.gov/pubmed/11382798

[9] https://www.ncbi.nlm.nih.gov/pubmed/23867520

[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4623318/

[11] https://www.ncbi.nlm.nih.gov/pubmed/12626690

[12] http://ajcn.nutrition.org/content/99/4/891.long

[13] http://ajcn.nutrition.org/content/86/4/995.long

[14] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555150/

[15] http://apps.who.int/iris/bitstream/10665/43411/1/WHO_TRS_935_eng.pdf

[16] https://en.wikipedia.org/wiki/Essential_amino_acid

[17] http://ajcn.nutrition.org/content/87/5/1554S.full

[18] https://www.ncbi.nlm.nih.gov/pubmed/15836464

[19] http://www.sciencedirect.com/science/article/pii/S0261561417302030

[20] https://optimisingnutrition.com/2016/11/19/the-alkaline-diet-vs-acidic-ketones/

[21] https://www.youtube.com/watch?v=E44yCNpP8bs

[22] https://www.researchgate.net/publication/13445647_Effects_of_Exercise_on_Dietary_Protein_Requirements

[23] http://bayesianbodybuilding.com/the-myth-of-1glb-optimal-protein-intake-for-bodybuilders/

[24] https://www.ncbi.nlm.nih.gov/pubmed/7903674

[25] https://www.ncbi.nlm.nih.gov/m/pubmed/22215165/

[26] https://en.wikipedia.org/wiki/Specific_dynamic_action

[27] https://intensivedietarymanagement.com/fasting-and-muscle-mass-fasting-part-14/

[28] http://online.liebertpub.com/doi/pdf/10.1089/met.2016.0108

[29] https://academic.oup.com/jcem/article-lookup/doi/10.1210/jc.2011-1377

[30] http://onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2005.00178.x/full

[31] http://www.simonandschuster.com.au/books/The-Dorito-Effect/Mark-Schatzker/9781476724232

[32] https://www.researchgate.net/profile/Fred_Provenza

[33] https://naturallynourishedrd.com/wp-content/uploads/2013/09/Interactive-Library-Nutrient_Correlation_Wheels-2.pdf

[34] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263749/

[35] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4215472/

why do my blood sugars rise after a high protein meal?

There is a lot of controversy and confusion over gluconeogenesis and the impact of protein on blood sugar and ketosis.

2017-06-03 02.27.38.png

Some common questions that I see floating around the interwebs include:

  • If you are managing diabetes, should you avoid protein because it can convert to glucose and “kick you out of ketosis”?
  • If you’ve dropped the carbs and protein to manage your blood sugars, should you eat “fat to satiety” or continue to add more fats until you achieve “optimal ketosis” (i.e. blood ketone levels between 1.5 and 3.0mmol/L)?

  • Then, if adding fat doesn’t get you into the “optimal ketosis zone”, do you need exogenous ketones to get your ketones up so you can start to lose weight?

  • And what exactly is a “well formulated ketogenic diet” anyway?

This article explores:

  • the reason that some people may see an increase in their blood sugars and a decrease in their ketones after a high protein meal,
  • what it means for their health, and
  • what they can do to optimise the metabolic health.

Protein is insulinogenic and can convert to glucose

You’re probably aware that protein can be converted to glucose via a process in the body called gluconeogenesis.  Gluconeogenesis is the process of converting another substrate (e.g. protein or fat[1]) to glucose.

  1. Gluco = glucose
  2. Neo = new
  3. Genesis = creation
  4. Gluconeogenesis = new glucose creation

All but two amino acids (i.e. the building blocks of protein) can be converted to glucose.  Five others can be converted to either glucose or ketones depending on the body’s requirements at the time.  Thirteen amino acids can be converted to glucose.

Once your body has used the protein it needs to build and repair muscle and make neurotransmitters, etc. any “excess protein” can be used to refill the small protein stores in the bloodstream and replenish glycogen stores in the liver via gluconeogenesis.

The fact that protein can be converted to glucose is of particular interest to people with diabetes who go to great lengths to keep their blood sugar under control.[2]

Someone on a very low carbohydrate diet may end up relying more on protein for glucose via gluconeogenesis compared to someone who can get the glucose they need directly from carbohydrates.[3]

Obtaining glucose from protein via gluconeogenesis rather than carbs is that it is a slow process and easier to control with measured doses of insulin compared to simple carbs which will cause more abrupt blood sugar rollercoaster.

How much insulin does protein require?

The food insulin index data[4] [5] [6] is an untapped treasure trove of data that can help us understand the impact of foods on our metabolism.

Our glucose response to carbohydrate

The food insulin index testing measured the glucose and insulin response to various foods in healthy people (i.e. non-diabetic young university students).

To calculate the glucose score or the insulin index pure glucose gets a score of 100% while everything else gets a score between zero and 100% based on the comparative glucose or insulin area under the curve response.  So we are comparing the glucose and insulin response to various foods to eating pure glucose.

As shown in the chart below, the blood glucose response of healthy people is proportional to their carbohydrate intake.   Meat and fish and high-fat foods (butter, cream, oil) tend to have a negligible impact on glucose.

Our insulin response to carbohydrates

The story is not so simple when it comes to our insulin response to food.

As shown in the chart below, the carbohydrate content of our food only partially predicts our short-term insulin response to food.  Low fat, low carb, high protein foods elicit a significant insulin response.

As you can see in the chart below, once we account for protein we get a better prediction of our insulin response to food.  It seems we require about half as much insulin for protein as we do for carbohydrate on a gram for gram basis to metabolise protein and use it to repair our muscles and organs.

image10

But does this mean we should avoid or minimise protein for optimal diabetes management or weight loss?  Does protein actually turn to chocolate cake?

What happens to insulin and blood sugar when we increase protein?

While protein does generate an insulin response, increasing the protein content of our food typically decreases our insulin response to food.

Increasing protein generally forces out processed carbs from our diet and improves the amount of vitamins and minerals contained in our food.[7]  Similarly, increasing the protein content of your food will also decrease your glucose response to food.

What happens when you eat a big protein meal?

The food insulin index testing was done using 1000 kJ or 240 calories of each food (i.e. a substantial snack, not really a full meal).  But what about if we ate a LOT of protein?  Wouldn’t we get a blood sugar response then?

The figure below shows the glucose response to 80g of glucose vs. 180g of protein (i.e. a MASSIVE amount of protein).  While we get a roller coaster-like blood sugar rise in response to the ingestion of glucose, blood sugar remains relatively stable in response to the large protein meal.[8] [9] [10]

So, if protein can turn to glucose, why don’t we see massive glucose spike?  What is going on?

The role of insulin and glucagon in glucose control

To properly understand how we process protein, it’s critical to understand the role of the hormones insulin and glucagon in controlling the release of glycogen release from our liver.

These terms can be confusing.  So let me spell it out.

  • The liver stores glucose in the form of glycogen in the liver.
  • Glucagon is the hormone that pushes glycogen out into the bloodstream as blood glucose.
  • Insulin is the opposing hormone that keeps glycogen stored in our liver.

When it comes to getting glucose out of the liver, glucagon is like the accelerator pedal while insulin is the brake.

When our blood glucose is elevated, or we have external sources of glucose, the pancreas secretes insulin to shut off the release of glycogen from the liver until we have used up or stored the excess energy.

Insulin helps to turn off the flow of glucose from our liver and store some of the excess glucose in the blood as glycogen and, to a much lesser extent, fat (via de novo lipogenesis).  It also tells the body to start using glucose as its primary energy source to decrease it to normal levels.

We can push the glucagon pedal to extract the glycogen stores in our liver by eating less carbohydrate (i.e. low carb or keto diets), eating less, or not eating at all (aka fasting)!

High insulin levels effectively mean that we have enough fuel in our blood stream and we need to put down the fork.

While fat typically doesn’t require significant amounts of insulin to metabolise, an excess of energy from any source will cause the body to ramp up insulin to shut off the release of stored energy from the liver and the fat stores.

Glucose, insulin and glucagon response to a high carbohydrate meal

At the risk of getting a little bit geeky, let’s look at how our hormones respond to different types of meals.

As shown in the chart below, when we eat a high carbohydrate meal insulin rises to stop the release of glycogen.  Meanwhile, glucagon drops to stop stimulating the release of glycogen from the liver.  When we have enough incoming glucose via our mouth, we don’t need any more glucose from the liver.[11]

Glucose, insulin and glucagon response to a high protein meal

When we eat a high protein meal, both glucagon and insulin rise to maintain steady blood glucose levels while promoting the storage and use of protein to repair our muscles and organs and make neurotransmitters, etc. (i.e. important stuff!).

In someone with a healthy metabolism, we get a nice balance between the insulin (brake) and the glucagon (accelerator).  Hence, we don’t get any glycogen released from the liver into the bloodstream to raise our blood sugar because the insulin from the protein is turning off the glucose from the liver.

This is why metabolically healthy people see a flat line blood sugar response to protein.

Insulin response to protein for people with diabetes

Things are different if you have diabetes.

Insulin resistance means that between our fatty liver and insulin resistant adipose tissue, things don’t work as smoothly.

While your blood sugar may rise or fall in response to protein, needs to rise a lot more while you metabolise the protein to build muscle and repair your organs.

Unfortunately, people who are insulin resistant may struggle to build muscle effectively due to insulin resistance.  Then the higher levels of insulin may drive them to store more fat in the process.[12]  Becoming insulin sensitive is important!

The chart below shows the difference in the blood glucose and insulin response to protein in a group of people who are metabolically healthy (white lines) versus people who have type 2 diabetes (yellow lines).[13]

People with diabetes may see their glucose levels drop from a high level after a large protein meal and will have a much greater insulin response due to their insulin resistance.  People with more advanced diabetes (i.e. beta cell burn out or Type 1 diabetes) may even see their blood sugar rise.  Their ability to produce insulin to metabolise the protein and keep glycogen in storage cannot keep up with the demand.

Drawing on the brake/accelerator analogy, it’s not necessarily protein turning into glucose in the blood stream via gluconeogenesis, but rather the glucagon kicking in and a sluggish insulin response that isn’t able to balance out the glucagon response to keep the glycogen locked away in the liver.

Healthy people will be able to balance the opposing hormonal forces of the insulin (brake) and the glucagon (accelerator), but if we are insulin resistant and/or don’t have a properly functioning pancreas (brake), we won’t be able to produce as much insulin to balance the glucagon response.

Someone who is insulin resistant has normally functioning accelerator pedal (glucagon stimulating glucose release in the blood) but a faulty brake (insulin).

Real life example

To unpack this further, let’s look at an example close to home.

The picture below is of a family meal (i.e. steak, sauerkraut, beans and broccoli) that we had when my wife Monica (who has Type 1 Diabetes) was wearing a continuous glucose meter.

The photo of the continuous glucose monitor below shows Monica’s blood sugar response after the meal which we had at about 5:30 pm.  Her blood sugar rises in response to the veggies and then comes back down as the insulin kicks in.

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The process to bring her blood sugars back under control from a few carbs in the veggies takes about two hours.

But over the next twelve hours, Monica’s blood sugar level drifts up as the insulin dose goes to work as she metabolises the protein.  For all intents and purposes though it looks like the protein is turning to glucose in her blood!

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This is not a one off.  We’ve seen this blood glucose response regularly.  The advent of continuous glucose meters makes this more evident as you can watch blood sugars rise over a long period after a high protein meal.

Many people with type 1 diabetes know they need to dose with adequate insulin for protein.  Once you work out how to reduce simple carbs, working out how to dose for protein is the next frontier of good insulin management.

It’s complicated and sometimes confusing.

More insulin or less protein?

So, what is the problem here?

Why are Monica’s blood sugars rising?

Is it too much protein?

Or not enough insulin?

I think the best way to explain the rise in blood sugars is that there is not enough insulin to keep the glycogen locked away in her liver and metabolise the protein to build muscle and repair her organs at the same time.

Meanwhile, the glycogen pedal is pushed down as it normally would be in response to a protein which is driving the glucose up in her bloodstream.

There is just not enough insulin in the gas tank (pancreas) to do everything that needs to be done.

So, if Monica had a choice, should she:

  • A. Keep her blood sugars stable and stop metabolising protein to repair her muscles and organs,
  • B.  Metabolise protein to build her muscles and repair her organs while letting her blood sugars drift up, or
  • C. Both of the above.

Personally, I think the correct answer is C.

While it’s probably not wise to go hog-wild with protein supplements and powders if you have diabetes, swinging to the other extreme to target minimal protein levels is a sure way to end up with a poor nutritional outcome.

According to Simpson and Raubenheimer in Obesity: the protein leverage hypothesis (2005), people with diabetes may actually need to eat more protein to ensure that they have adequate amounts to build lean muscle mass given that higher levels of gluconeogenesis may cause more protein loss to glucose due to their insulin resistance.

One source of protein loss is hepatic gluconeogenesis, whereby amino acids are used to produce glucose. This is inhibited by insulin, as is the breakdown of muscle proteins to release amino acids, and therefore occurs mainly during periods of fasting (or low carb).

However, inhibition of gluconeogenesis and protein catabolism is impaired when insulin release is abnormal, insulin resistance occurs, or when circulating levels of free fatty acids in the blood are high. These are interdependent conditions that are associated with overweight and obesity, and are especially pronounced in type 2 diabetes (12,34).

It might be predicted that the result of higher rates of hepatic gluconeogenesis will be an INCREASED requirement for protein in the diet.

A lot of my early motivation in developing the Optimising Nutrition blog was to understand which foods provoked the least insulin response and how to more accurately calculate insulin dosing for people with diabetes to help Monica get off the blood glucose roller coaster.

Like Ted Naiman, I thought if we reduced the insulin load from our food (including minimising protein) we would have a pretty good chance of losing a lot of weight (just like someone with uncontrolled type 1 diabetes).

I no longer think we need to restrict or avoid protein to manage insulin resistance.  However, there’s no need to go to the other extreme and binge on protein if you are injecting insulin.

Worrying about getting too little or too much protein is largely irrelevant.  We will get enough protein when we eat a nutritious diet.  Left to its own devices, our appetite typically does a good job of seeking out adequate protein to suit our current needs.

Meanwhile actively aiming to minimise protein will make it harder to maintain lean muscle mass which is critical to glucose disposal and insulin sensitivity.

If you see your blood sugar levels rise due to protein, it is likely due to inability to produce enough insulin rather than too much protein.  If you are injecting insulin you may need to dose with more insulin to allow you to utilise the protein in your diet to build and repair your body.

Basal and bolus insulin

One option to minimise the adverse effects of excess insulin is to focus on reducing the insulin load of our diet and eat only high-fat foods that have a low proportion of insulinogenic calories (i.e. ones towards the bottom left of this chart).

If you are highly insulin resistant and obese, this will work like magic, at least for a little while.

People who suddenly stop eating processed junk carbs and eat more fat often find that their appetite plummets as the insulin demand of their food drops and they are more easily able to access their own body fat.[14] [15]

But this is only part of the story.  Again, we can learn a lot about insulin from people with Type 1 diabetes who have to manually manage their insulin dose.

In diabetes management there are two kinds of insulin doses:

  1. basal insulin, and
  2. bolus insulin.

The bolus insulin is the insulin for the food we eat.

The basal insulin is a steady flow of insulin that is required throughout the day and night.

Without the basal insulin, we would disintegrate into uncontrolled gluconeogenesis and ketoacidosis (e.g. uncontrolled type 1 diabetes).

In a person eating a typical western diet around half the insulin given in a day is for the food and half is basal insulin. The chart below shows the daily insulin dose of a person with type 1 diabetes eating a standard diet.  The white component is the basal, and the black is the bolus for their food.

In someone following a low carb diet only around 30% of the insulin is for the food and 70% is basal insulin as shown below in my wife Monica’s daily insulin dose shown below.

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We can only reduce our insulin requirements marginally by changing our diet.   We always need basal insulin.  If we’re insulin resistant, we’ll need more.

Like caffeine or alcohol, we become more sensitive to insulin when we are exposed to less of it.  As we reduce the insulin load of our diet, our insulin sensitivity will improve.

But not everyone who follows a low carb diet instantly turns into a super athlete.  There has to be more to the story.

How to improve your basal insulin sensitivity

In addition to modifying our diet, we can also improve our blood glucose control by maximizing our body’s ability to dispose of glucose without relying on insulin (i.e. non-insulin mediated glucose uptake).  We enhance our insulin sensitivity and our ability to use glucose by building more lean muscle mass.

I used to think that if we just dropped the insulin load of our diet down far enough, we would be able to lose weight, a bit like someone with uncontrolled type 1 diabetes.  But now I understand that there will always be enough basal insulin in our system to store excess energy (regardless of the source) and stop our liver from releasing stored energy.

While a diabetic can reduce their insulin requirements for food by eating food with lots of fat, they can actually end up insulin resistant and need more basal insulin if they drive over abundance of energy, regardless of whether it’s from protein, fat or carbs.[16]

While ketones can rise to quite high levels when fasting (which is great), I fear that some people are chasing high ketone levels with lots of dietary fat and the excess energy may lead to insulin resistance in the long term.

Dr Bernstein’s approach

The method recommended by Dr Bernstein (who has type 1 diabetes himself) is typically lower in carbs, adequate protein (depending on whether you are a growing child) and moderate in fat.

Even at 83, Dr B feels it is important to maintain lean muscle mass through regular exercise to maximise his insulin sensitivity.

Will too much protein “kick me out of ketosis”?

While the ketogenic diet is becoming popular, I think most people who are interested in it do not necessarily require therapeutic ketosis, but rather are chasing weight loss or blood sugar control/diabetes management.

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If you are managing a condition that benefits from high levels of ketosis (e.g. epilepsy, dementia, cancer, traumatic brain injury, Alzheimer’s) then limiting protein may be necessary to ensure continuously elevated ketone levels and reduce insulin to avoid driving growth in tumour cells and cancer.  

Giving the burgeoning interest in the ketogenic dietary approach, I think it’s important to understand the difference between exogenous ketosis and endogenous ketosis.

  • Endogenous ketosis occurs when a person eats less than the body needs to maintain energy homeostasis and we are forced to up the glycogen in our liver and then our body fat to make up the difference.
  • Exogenous ketosis (or nutritional ketosis) occurs when we eat lots of dietary fat (or take exogenous ketones), and we see blood ketones (beta hydroxybutyrate) build up in the blood. We are burning dietary fat for fuel.

Higher levels of ketones in the blood are an indication that you are eating more fat than you are burning.  Having some level of blood ketones is an indication that your insulin is low, but whether your blood ketones are high or low should not be a major cause for concern as long as your blood glucose levels are also low.  Unless we are doing a long term fast, we will all be somewhere on the spectrum between exogenous and endogenous ketosis.

Keep in mind though that most of the beneficial things we attribute to “ketosis” and the “ketogenic diet” occurs when we are in endogenous ketosis (i.e.  when fat is coming from our body, not our plate or coffee cup).

As detailed in the popular article What are Optimal Ketone and Blood Sugar Levels in Ketosis? it seems that lower levels of total energy (i.e. towards the left of this the chart below) is a better place to be, particularly if we are chasing weight loss or diabetes management.

Our blood ketones may not be as high when we are in endogenous ketosis, but that’s OK because most of the good stuff happens in a low energy state.  

Endogenous ketosis Exogenous ketosis
Low total energy (i.e. blood glucose + blood ketones + free fatty acids) High total energy (i.e. blood glucose + blood ketones + free fatty acids)
Stored energy taken from body fat for fuel Ingested energy used preferentially as fuel
Stable ketone production all day Sharp rise of ketones for a short duration.  Need to keep adding fat or exogenous ketones to maintain elevated ketones.
Insulin levels are low which allows release of glycogen from our liver and fat stores Insulin levels increase to hold glycogen in liver and fat in adipose tissue
Mitochondrial biogenesis, autophagy, increase in NAD+, increase in SIRT1 Mitochondrial energy overload, autophagy turned off, decrease in NAD+
Body fat and liver glycogen used for fuel Liver glycogen refilled and excess energy in the bloodstream stored as fat.

Summary

  • Gluconeogenesis is the creation of new glucose (generally from protein).
  • Protein requires about half as much insulin as carbohydrate to metabolise.
  • Increasing protein intake will generally improve our blood glucose and insulin levels.  Protein forces out processed carbohydrates, increasing the nutritional quality of our diet and helps us to build muscle which in turn burns glucose more efficiently.
  • In a metabolically healthy person glucagon balances the insulin response to protein, so we see a flat line blood sugar response to even a large protein meal.
  • If you cannot produce enough insulin, you may see glucose rise as your body tries to metabolise the protein and keep the energy stored in the liver at the same time.
  • The insulin for the food we eat (bolus) represents less than half of our daily insulin demand. We can improve our basal insulin sensitivity by building lean muscle mass and improving mitochondrial function via a nutrient dense diet.
  • If we are aiming for weight loss and health, then low blood sugars and low ketones will be more desirable rather than chasing high ketone levels via exogenous ketosis.

references

[1] http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1002116

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636610/

[3] https://optimisingnutrition.com/2015/06/04/the-goldilocks-glucose-zone/

[4] https://ses.library.usyd.edu.au/handle/2123/11945

[5] https://optimisingnutrition.com/2015/03/23/most-ketogenic-diet-foods/

[6] https://optimisingnutrition.com/2015/03/30/food_insulin_index/

[7] https://optimisingnutrition.com/2017/05/27/is-there-a-relationship-between-macronutrients-and-diet-quality/

[8] https://www.ncbi.nlm.nih.gov/pubmed/16694439

[9] http://caloriesproper.com/dietary-protein-does-not-negatively-impact-blood-glucose-control/beef-vs-glucose/

[10] http://www.ketotic.org/2013/01/protein-gluconeogenesis-and-blood-sugar.html#¹

[11] https://books.google.com.au/books?id=3FNYdShrCwIC&printsec=frontcover&dq=marks+basic+medical+biochemistry&hl=en&sa=X&ei=-ctaVcivOJfq8AXL84CAAw&redir_esc=y#v=onepage&q=glucagon&f=false

[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997013/

[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC524031/

[14] https://docmuscles.com/

[15] https://optimisingnutrition.com/2017/01/15/how-optimize-your-diet-for-your-insulin-resistance/

[16] https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-11-23

 

 

post last updated August 2017