Perhaps the biggest differentiator between keto and every successful version of a lower-carb diet (e.g. Atkins, Paleo, Bernstein, Banting, Carnivore, etc.) is the misguided fear of ‘excess protein’ to keep ketones high, insulin low and avoid gluconeogenesis.
Ever since Jimmy Moore discovered that protein could convert to sugar via gluconeogenesis and therefore lower your blood ketones, it seems that many of the low-carb and keto groups have been confused about and afraid of protein. Many keto gurus recommend doing whatever you can to minimise protein and replace those calories with fat to maximise ketosis.
When we were both speakers on the 2016 Low Carb Cruise, Jimmy told me that he aims for Dr Ron Rosedale’s recommendation of 0.8 g/kg protein. He has encouraged his followers to do the same for fear of protein ‘turning into chocolate cake in your bloodstream‘. Sadly, many of these people, believing that protein is bad, and fat is good, then can’t work out why their weight loss has stalled, even though they are ‘doing everything right’.
Before we get into recommended amounts of protein, we should touch on how protein intake is measured. A lot of the confusion comes because people are using slightly different units to measure protein, even though they are often talking about pretty much the same protein intake in practice.
The table below shows some examples of ways that protein recommendations are given. People talk about protein in terms of body weight, lean body mass, ideal body weight or percentages. Then some people are talking about protein per kilogram while others are talking in pounds.
|Total body weight||g/kg BW g/lb BW||Easy to measure because most people don’t measure their body fat.||Doesn’t consider body fat which is less metabolically active.|
|Lean body mass||g/kg LBM g/lb LBM||More accurate because it accounts for active lean tissue.||Requires some understanding of body fat levels.|
|Ideal body weight/Reference body weight||g/kg IBW g/lb IBW||Doesn’t require the measurement of body fat.||Difficult to agree on ideal body weight.|
|Percentage of calories||%||Simple||Doesn’t account for whether you are in an energy surplus or deficit.|
Our preference is to use protein per lean body mass (i.e. g/kg LBM) because it’s your muscles and organs that are metabolically active, while your body fat is, for the most part, just your fuel tank that comes along for the ride.
You can use a DEXA scan (expensive, but the most accurate), bioimpedance scale (easy to do regularly at home to compare your progress) or comparison pictures (like the ones below) to estimate your level of body fat (% BF). If you’re interested, you could calculate your LBM using the following formula:
lean body mass (LBM) = bodyweight weight x (100% – BF%) / 100.
Calculating your body fat levels or protein intake to a high degree of accuracy is not necessary for most people, given the protein target should generally be treated as a minimum. To calculate your target protein intake, you can use the simple macro calculator here.
According to Cahill’s starvation studies, 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 stores in our liver and muscles, the body will turn to its internal protein stores (i.e. muscles, organs etc.) and, to a lesser extent, fat (the glycerol backbone) to obtain glucose via gluconeogenesis.
The figure below (below from Quantitative Physiology of Human Starvation: Adaptations of Energy Expenditure, Macronutrient Metabolism and Body Composition) shows that we use less protein for energy, the longer we go without food. After a couple of days with no food, fat and ketosis kick in to supply much of the energy deficit.
In the first few days, you will be using around 400 calories from protein (i.e. about 100 g of protein per day). Over the long term, this decreases to 250 calories worth (60 g of protein) per day.
While protein requirements do reduce during extended fasting, this amount of protein you are still pulling from your muscles and organs is still significant. If you fast for a couple of days every week, you will need to make up for that protein across the week to prevent loss of lean muscle over the long term.
When you refeed, your body will seek out food to replenish energy and nutrients, especially protein. If you do not prioritise protein when you refeed, you will consume more energy to get the protein that your body requires. This is why so many people find themselves losing and regaining the same weight when they attempt extended fasting without paying enough attention to food quality when they refeed. Regardless of how long you chose to fast, nutrient focused refeeding (especially protein) is critical.
Over the short term, gluconeogenesis and autophagy are not necessarily a bad thing. Your body will increase autophagy (self-eating) and clean out the old, sick and superfluous parts of the body to be used for fuel. After a fast, the body is primed and highly insulin sensitive and ready to build new muscle.
The reality is, most people see their lean mass drop during any form of energy restriction, including extended fasting. It’s ideal if you can keep an eye on your changes in lean mass over time.
While no method of measuring body fat is perfectly accurate, tracking your change against your baseline (e.g. with bioimpedance scales that you can use at home every day) will give you an understanding of whether you should increase your protein intake if you find you are losing muscle rather than fat.
The Daily Recommended Intake (DRI) for protein is 0.84g/kg of body weight (BW) while the Estimated Average Requirement (EAR) is 0.68g/kg BW. However, it’s critical to keep in mind that the DRI is a recommended minimum per day to prevent diseases related to protein deficiency.
Recent studies have indicated that higher quantities of protein may be necessary, particularly for older people, who require at least 1.2 to 2.0 g/kg of protein per day (total body weight), to optimise physical function.
According to Raubenheimer and Simpson (see Obesity: the protein leverage hypothesis), the reason that older people tend to require more dietary protein is that they are more likely to be insulin resistant and hence have excessive levels of gluconeogenesis. The protein they eat is being ‘lost’ to glucose in the bloodstream.
Also, if you are consuming minimal carbs, your body will make the glucose it needs from the protein you eat. Hence, you may need extra protein to supply the glucose your body requires. Without adequate dietary protein, your appetite will increase to ensure you get enough. If your diet has a lower proportion of protein you will need to consume a lot more food to get the protein (and other nutrients) you need. So, rather than avoiding protein, it’s better to target a higher protein percentage if your goal is to lower your insulin, reduce body fat and improve your insulin sensitivity. A diet with a higher percentage of protein will also improve satiety, and in time, lead to fat loss and lowered blood sugar and insulin levels.
If you’re active, you’ll need more protein for growth and repair. If you’re sedentary, you’ll need less. Most of the time, our appetite sorts this out, and we crave more protein if we are doing a lot of resistance training. 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 the study, Effects of Exercise on Dietary Protein Requirements (Lemon, 1999):
- a strength athlete required at least 1.8 g/kg body weight to maximise muscle protein synthesis;
- an endurance athlete should consume at least 1.4 g/kg body weight; and
- someone who is sedentary needs at least 0.9 g/kg body weight.
Note: These values should be seen as minimums during weight maintenance. More protein may be beneficial for satiety, improved nutrient density or prevent loss of lean mass when losing fat.
If you are active and/or doing resistance training, you will have a greater requirement for protein during fat loss in an energy deficit. As shown in the chart below from a review paper by Stuart Phillips, lean muscle mass is best preserved when we have at least 2.6 g/kg total body weight where there is an aggressive deficit (e.g. 35%), while a lower protein intake of 1.5 g/kg body weight seems to be adequate where we have a less aggressive deficit.
Many people are concerned that protein will raise their blood sugars. However, as shown in the chart below from my analysis of the Food Insulin Index data, foods with more protein are likely to be lower in carbohydrates (which tend to drive up blood sugars the most). Higher protein foods tend to displace carbohydrates in the diet. My analysis of the Food Insulin Index data shows that protein does not influence blood sugars post-meal (see What affects your blood sugar and insulin (other than carbs)? for more detail).
Our analysis of the Food Insulin Index data also shows that protein does not influence blood sugars post-meal (see What affects your blood sugar and insulin (other than carbs)? While protein can be converted to glucose, this does not occur immediately. When you eat protein, your pancreas secretes glucagon, which pushes glycogen from your liver into your bloodstream as glucose. The glycogen response is balanced by insulin, and hence blood sugar remains stable for most people.
Many metabolically healthy people find their blood sugars decrease after a high-protein low-carb meal due to the insulin response from the protein, particularly in the morning when their body is primed to store energy after an overnight fast.
Conversely, people who are insulin resistant may find that the insulin that they release in response to protein does not act as effectively to balance the glucagon, and hence their blood sugars rise. Some people see this rise in blood glucose as a reason to avoid protein. However, because a significant amount of their dietary protein is being used to supply the glucose they need, they actually need to focus more on getting enough protein to ensure that there are enough amino acids available for muscle protein synthesis and other critical bodily functions. This excess gluconeogenesis can cause their appetite to ramp up to ensure they get the protein they need.
If you do see your blood sugars rise significantly after a very low-carb high-protein meal, you likely have a significant amount of insulin resistance due to being above your Personal Fat Threshold. Rather than avoiding protein and prioritising fat in a misguided effort to improve your insulin resistance, you actually need to do the opposite!
People with Type 1 Diabetes on a low-carb diet know that they require extra insulin for dietary protein as well as carbohydrates. Some people use long-acting insulin to better match the slower insulin demand for protein. Since we’ve been using the AndroidAPS closed-loop insulin pumping system, my wife, Monica, has been using the e-carbs function where you can give a drip-feed of insulin for the protein in a meal over 5 hours or so.
Because insulin works both to build and repair your muscles as well as keep your stored energy locked away while you are eating, you will need a little extra insulin for a number of hours after you consume a high-protein meal.
Protein requires about half as much insulin as carbohydrates over 2 hours. But as we will see later, the fact that protein requires bolus insulin (i.e. the insulin associated with the food we eat) should not be seen as a concern because protein drives satiety, which will allow your stored body fat to be used and will reduce your basal insulin requirements and total insulin demand across the whole day.
Medications such as injected insulin help to manage the symptoms of Type 2 Diabetes (i.e. elevated blood sugars), but do little to reverse the underlying cause (i.e. energy toxicity), and can make it harder to lose unwanted body fat.
Injected insulin forces your body to hold fat in storage and can make you hungrier, which can lead to weight gain. As you lose weight, you will see a reduced need for both injected basal and bolus insulin due to improved insulin sensitivity as you start to lose excess body fat.
If you are taking any diabetes-related medications (especially injected insulin), you should pay particular attention to your blood sugars and work with your health care team to adjust your medications to ensure that your blood sugars don’t go lower than you feel comfortable with (e.g. below 4.0 mmol/L or 72 mg/dL). Not only will you feel unwell below this level, but you will likely want to eat anything and everything until your blood sugar returns to normal.
Establishing a predictable routine is crucial if you are taking diabetes medications. If you radically change your eating pattern (e.g. skipping a whole day of eating or multi-day fasts) your insulin needs will plummet, and you will risk hypoglycemia (i.e. low blood sugars).
Optimising Nutrition advisor Dr Ted Naiman has recently been advocating for more intelligent consideration of the Protein:Energy Ratio based on the Protein Leverage Hypothesis which demonstrates that we keep eating until we get the protein we need.
Unless you are eager to weigh and measure everything you eat for the rest of your life and battle with the resultant hunger, optimising your diet for satiety is the key to managing your food intake and your weight.
The key to increasing satiety and eating less is to increase your PROTEIN PERCENTAGE. Conversely, the way to eat more (to grow, or fuel for high levels of activity) is to decrease your PROTEIN PERCENTAGE by adding more easily accessible energy from fat and carbs.
Our analysis of half a million days of data from MyFitnessPal users also aligns with the Protein Leverage Hypothesis. The percentage of protein in your diet has the largest influence on satiety of all the macronutrients and essential micronutrients (yes, we have tested them all!).
Managing your appetite and spontaneously eating less is not necessarily about eating a lot more protein, but rather incrementally dialling up the percentage of protein in your diet (by reducing your intake of fat and/or carbs).
By contrast, many low carb or keto communities advocate for the exact opposite to break a fat loss stall (i.e. avoid protein due to its short-term impact on insulin and eat more fat to drive elevated ketones). Meanwhile, many in the low fat or plant-based community also advocate for avoiding protein and more carbohydrates. Although we live in a postmodern world where everyone is entitled to their own opinion, science and human metabolism tend to follow a similar pattern regardless of our beliefs or how we would like it to behave.
Our analysis of data from 40,000 days of data from people using Nutrient Optimiser also shows that as we consume a higher percentage of protein, our overall calorie intake will come down. We simply struggle to overeat foods that have a higher percentage of protein. Sadly, the average population intake of protein (13-15%) aligns with the lowest satiety response.
It’s probably not wise or sustainable to try to jump from 10 to 50% overnight. However, if you want to lose fat from your body, then slowly increase your protein percentage by dialling back the easily accessible energy in your diet from fat and carbohydrates.
Analysis of our data from people using Nutrient Optimiser shows that most people prioritising nutrient density consume around 1.8 g/kg LBM protein. We tend to see the best satiety response and the quickest weight loss in the Nutritional Optimisation Masterclass when people can get at least this level and then progressively dial back fat and carbs.
Prioritising adequate dietary protein ensures you don’t lose precious muscle and other lean mass (e.g. your vital organs). Reducing carbs from your diet helps to reduce blood sugars while reducing dietary fat helps to promote fat loss from the body.
Studies tend to be mixed on whether higher levels of protein will decrease ketones. However, many people report anecdotally that their ketones decrease with higher protein levels in their diet. This makes logical sense, given that protein provides oxaloacetate which enables fat to be burned in the citric acid cycle (rather than resorting to ketosis, which is a less efficient process).
However, to understand if you need to be concerned about losing your ketones, you need to consider your goals.
- Do you want to be in exogenous ketosis, with ketones coming from your diet to achieve therapeutic levels of ketones for the management of epilepsy, Alzheimer’s or dementia, or
- are you aiming for endogenous ketosis, with ketones coming from your body for diabetes reversal, fat loss and improved metabolic health?
If you require therapeutic ketosis, then you may want to keep your protein low and supply added dietary fat to force exogenous ketosis. But if your goal is fat loss and improved metabolic health, you should prioritise satiety and nutrient density and may just end up in endogenous ketosis (i.e. ketones coming from the fat being burned on your body) as a side effect.
Foods with a higher percentage of protein tend to be more nutritious. Fear of protein, for whatever reason, leads people to eat more due to low satiety. They get less of the nutrients they need and crave more food to compensate, thus perpetuating an unhealthy cycle of eating to excess but suffering nutrient deficiency. If you set your diet up primarily for exogenous ketosis, you are likely also setting yourself up for nutrient deficiencies and cravings for more protein and nutrients.
On the upside, protein powders can provide highly bioavailable protein that enables you to top up if you are struggling to get enough protein in your diet. This is great for very active people who are struggling to consume enough food to support their activity levels or to grow bigger or stronger.
There have been a number of studies led by Jose Antonio where they have tried to overfeed active people massive amounts of protein powders (i.e. up to 4.4 g/kg/day or five times the recommended daily allowance for protein). The first observation was that people struggle to eat that much protein, even from powders. The second was that the participants did not gain weight or body fat even though they were consuming well in excess of their energy requirements. The body struggles to convert dietary protein to body fat. But at the same time, participants did not lose weight by eating more protein.
The downside is that protein powders (and all the food products that contain them) won’t provide you with the same nutrient density as whole foods. While they will provide heaps of amino acids per calorie, they don’t provide a high level of vitamins and minerals compared to whole food.
And perhaps most importantly, powders won’t provide the same level of satiety as whole food protein sources. Whey protein is a waste product that is leftover from the cheese-making process. Because it is already highly processed, your body doesn’t need to do much work to convert it to energy in your body, thus the dietary-induced thermogenesis will be much lower for protein powders compared to whole food minimally processed forms of protein.
So, as always, do whatever you can to prioritise nutrient-dense whole foods and use supplements only as a last resort.
One of the primary functions of your kidneys is to filter your blood. The estimated glomerular filtration rate (eGFR) is a common test that provides an indication of how well your kidneys are working. The eGFR is based on the amount of creatinine (a waste product from the muscles from the breakdown of protein) in your bloodstream.
Some people become concerned when they see these high eGFR levels and think that the protein they are eating is causing kidney dysfunction. However, it probably shouldn’t be surprising that people who are eating more protein are carrying more muscle than average or who are supplementing with creatine would see higher creatinine in their bloodstream. Creatine, found in meat and fish, is one of the most well researched and beneficial supplements for strength and cognitive performance.
If you have late-stage kidney failure and are on dialysis, it may be worth talking to your nephrologist about how much protein they think you should be consuming. However, the reality is that we don’t tend to see active bodybuilders getting kidney failure due to high protein diets.
The vast majority of people on kidney dialysis have elevated blood sugar and blood pressure. According to Dr Ted Naiman, people who tend to consume more protein tend to have larger and higher functioning kidneys. Eating more protein is akin to beneficial resistance training for your kidneys. Just like you don’t want your muscles to weaken through disuse, you don’t want your kidneys to atrophy with age.
A 2018 meta-analysis by Professor Stuart Phillips Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis found that higher protein intakes do not adversely influence kidney function in healthy adults.
‘Rabbit starvation‘ is a term used to describe what happens to lean and active people when they only have lean protein foods with minimum fat available.
The term originated in active pioneers and explorers who had to live on available game meat. While rabbits are plentiful, they also have very low levels of fat. So, people living on rabbit alone just can’t get enough energy to sustain low levels of body fat. However, for most of us who have plenty of body fat to burn, this is not going to be an issue! Once we get adequate protein, their appetite for high-protein foods shuts down, and they search for easily accessible energy from fat and/or carbs.
If you are getting super lean and only have high-protein foods available to eat, then ‘rabbit starvation’ may be an issue for you. But as long as you have a significant amount of body fat to burn, then ‘rabbit starvation’ is not something you need to be concerned about.
If your only goal is to have elevated blood ketones, then keeping your protein intake low may help. But if your goal is fat loss, improved metabolic health or diabetes reversal, then prioritising a higher percentage of protein in your diet is a smarter approach (regardless of your ketone levels).
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Sample the other chapters of Big Fat Keto Lies
- Big Fat Keto Lies: Introduction
- A brief history of low carb and keto movement
- Keto Lie #1: ‘Optimal ketosis’ is a goal. More ketones are better. The lie that started the keto movement.
- Keto Lie #2: You have to be ‘in ketosis’ to burn fat
- Keto Lie #3: You should eat more fat to burn more body fat
- Keto Lie #4: Protein should be avoided due to gluconeogenesis
- Keto Lie #5: Fat is a ‘free food’ because it doesn’t elicit an insulin response
- Keto Lie #6: Food quality is not important. It’s all about reducing insulin and avoiding carbs
- Keto Lie #7: Fasting for longer is better
- Keto Lie #8: Insulin toxicity is enemy #1
- Keto Lie #9: Calories don’t count
- Keto Lie #10: Stable blood sugars will lead to fat loss
- Keto Lie #11: You should ‘eat fat to satiety’ to lose body fat
- Keto Lie #12: If in doubt, keep calm and keto on