Eat Like the Animals: The Origins of the Protein Leverage Hypothesis

Most diet books start with an agenda centred around a pre-determined nutrition belief.  The rest of the book then tries to compile enough science around it.  

Eat Like the Animals is the opposite, or at least that was what I thought until I dug into the data behind the biggest and most expensive mouse study ever! 

For the most part, Eat Like the Animals is data-driven biology at its best.  Professors Raubenheimer and Simpson recount their journey of nutritional enlightenment while keeping it entertaining and making it memorable!

Our data analysis aligns with Raubenheimer and Simpson’s Protein Leverage Hypothesis, which shows that getting adequate protein is critical to satiety and ensuring you don’t eat more than you need to. 

However, as you’ll see, the balance between enough and too much protein is always controversial and often a tough balance to find. 

In the second half of this article, we dig into the controversy around protein and longevity to provide some balance and clarity.

The Origins of the Protein Leverage Hypothesis

University of Sydney Professors Stephen Simpson and David Raubenheimer began as entomologists studying the eating habits of insects. 

They didn’t suspect they would discover THE most critical factor that drives humans and every other creature to eat – to get enough protein. 

Through their fascinating and detailed research and painstaking studies, they found they could create radically different outcomes regarding obesity and longevity by manipulating what these insects ate. 

Specifically, they discovered that insects—and eventually other animals—would continue to eat until they satisfied their protein demands.

With the publication of their 2005 paper, Obesity: The Protein Leverage Hypothesis, they explained this phenomenon and the Protein Leverage Hypothesis as we know it was born. 

In the book, Eat Like the Animals, they recount how they submitted the manuscript for review and heard nothing – crickets – for months until it was finally returned with minimal suggestions and later published.   

Later, they were told that the delay was because the reviewers couldn’t believe something so simple but crucial in biology had been missed for so long.  The most critical factor in managing appetite and obesity had been hiding in plain sight! 

Since then, the ‘protein leverage hypothesis’ has been verified in many organisms, from slime to apes and, of course, humans. 

How It Started

In Eat Like the Animals, Raubenheimer and Simpson make bug biology fascinating. 

Did you know crickets turn cannibalistic and eat each other if they can’t get enough dietary protein?  

Their motivation to march across the desert by the billions is not only to find food but also to avoid being eaten by the bug(s) following in tow!  

Similar to crickets, our craving for protein is stronger than any other appetite signal we have.  Per our extensive satiety analysis and Raubenheimer and Simpson’s findings, we tend to consume fewer calories if we consume foods and meals with a higher protein %. 

To put it another way, we consume fewer calories when our diets have less energy from fat and carbs and a higher percentage of energy from protein.  Conversely, we tend to eat more when refined and processed fat-and-carb combo foods dominate our modern diet.

As shown in the chart below from our satiety analysis of the diets of thirty-five thousand humans (not bugs), we tend to eat fewer calories when our diet lass less energy from fat and carbs and a higher protein %. 

What Is a Balanced Diet?

While we would like to think our conscious mind is in control, it’s not.  Your instinctual cravings are constantly working to ensure you get the right balance of macronutrients and micronutrients that you need from the food you have available. 

There is no ‘perfect food’, so we mix and match to ensure we get what we need over the long term. 

To illustrate, in the following chart, eating around the green line represents a ‘balanced’ diet.  Here, the aqua line represents someone consuming adequate protein to support lean muscle mass and just enough easily accessible energy from carbs or fat to fuel activity and maintain body weight.  

But unfortunately, there isn’t one universally ‘perfect food’ that provides a balance of protein and energy (from fat and carbs).  Thus, we eat a little of this and that until we uncannily end up at our target of enough protein and energy.  

Simpson and Raubenheimer were amazed as they tracked numerous insect and animal diets in the wild.  Although it appeared random at the time, they found that the relative macronutrient intakes always balanced out in and around the same point when they tallied up the data!

To cut to the chase, the problem in our modern environment is that we are constantly surrounded by foods that have inadequate protein and we have to keep eating more food to get the protein we require.  Thus, we end up consuming excess calories.  We end up stuck above the unbalanced’ low protein:energy ratio line and have to keep eating to get the protein we require.

After I initially published this review, Raubenheimer and Simpson reached out to me and later agreed to discuss protein leverage in this podcast interview.  Check it out to learn more about protein leverage in their own words. 

Why We Love Steak and Chips

Have you ever wondered why a meal of steak and chips is so popular?  

A big juicy filet mignon and some warm, salty, crunchy, and greasy potatoes. 

What’s not to love!?  As you will see, it’s the ‘perfect’ combination to balance our protein and energy requirements. 

But most people don’t only eat baked (oil-free) potatoes ALL the time – they’d only be getting fast-acting starchy carbs with minimal protein and fat.    

Similarly, most people don’t only eat lean steak ALL the time – they wouldn’t get enough energy from fat or carbs. 

The chips are yummy because they provide accessible energy from the reward-stimulating fat-and-carb combo.  But eventually, we crave protein, and our appetite will send us in search of steak.  

Conversely, if we started out eating just lean, high-protein steak with minimal fat, we would soon crave some fat or carbs to get the energy we need to operate.  Because pure protein is difficult to convert into usable energy (ATP), your appetite will eventually send you in search of some easy fuel.

Even carnivorous diet followers know they need enough fat to prevent hunger, cravings and excessive weight loss!  This is why carnivore enthusiasts like Dr Paul Saladino recommend consuming upwards of 65% of their energy from fat, depending on their activity levels. 

Lean protein alone just doesn’t provide enough energy.  

In their research, Raubenheimer and Simpson found this trend plays out in animal models over and over.  When animal X or insect Y is fed a lot of protein, and animal B or insect A is fed a lot of carbs and fat, they innately gravitate towards foods that contain the macronutrient they’re short of when they have access to both food sources. 

Amazingly, they innately eat just enough of the right food source and consistently arrive at similar targets.  A ‘balanced’ diet differs amongst different species and people at different life stages, activity outputs, and stress levels. 

Older people and pregnant women need a bit more protein.  Younger people or active athletes often get away with a lower protein % because they are using a lot more energy. 

But regardless, our appetite has an incredible way of navigating us back to the balanced diet we require!

While we like to think we can count calories and consciously exert enough self-restraint to limit our intake, resistance is futile over the long term unless you get the right balance of protein vs energy for your body and activity levels.  

Simpson and Raubenheimer have coined their blue-red heat map (below) as their Geometric Framework for Nutrition.  This represents the protein % vs fat % plot of their subjects’ diet and shows that we tend to eat fewer calories when we have more protein.  Conversely, we tend to consume more energy when we eat foods with a lower percentage of total calories from protein (protein percentage, or protein %).  

Our recent satiety index analysis also shows that we consume way fewer calories when dialling the protein % of our diet.  For more detail, see High Satiety Index Foods:  Which Ones Will Keep You Full with Fewer Calories?

However, while foods with a super high protein % may provide greater satiety per calorie, they may be a little aggressive for sustainable long-term weight loss.   Hence, it’s ideal to understand your typical protein, carb and fat intake and tweak your goal to enable you to achieve it. 

In our Macros Masterclass, we guide Optimisers to adjust their macros each week to ensure they lose between 0.5 and 1.0% weight per week

The Problem with Low Protein Diets

We get into trouble when we only have access to hyper-palatable, low-protein, fat-and-carb combo foods that are the equation for modern junk food.  Consequently, we must exceed our energy requirements to hit our protein requirements.  

In Eat Like the Animals, Raubenheimer and Simpson emphasised that we don’t have to consume massive amounts of protein to put protein leverage into action.  Instead, we only need to increase our protein intake slightly above the current average percentage.  

In the examples from the book’s final chapter, they talk about a scenario where a subject (Mary) slipped from 15% to 13% of her total calories from protein, which resulted in her consuming an average of 290 more calories per day!  Over time, this led to an insidious weight gain.  In contrast, shifting from 15 to 17% allowed her to reduce her calorie intake by almost 150 calories per day.  

A recent study, Higher protein intake during caloric restriction improves diet quality and attenuates loss of lean body mass, showed that participants only required a slight increase in protein % (from 18 to 20%) to improve satiety and food quality and decrease the loss of lean mass. 

It’s important to note that we don’t need to eat more protein; instead, it requires us to make slightly better food choices so we can increase the percentage of our total calories from protein.  Usually, this means replacing irresistible low-protein foods like chips, pizza, or doughnuts that combine carbs and fat for a protein-rich serving of fish, poultry, or meat.  

Our analysis of Cronometer and MyFitnessPal data takes a slightly different approach but arrives at the same conclusions as most of their work.  Regardless, foods with a higher percentage of protein are simply harder to overconsume.  As shown in the chart below from our analysis of data from our Optimisers, increasing protein % aligns with a moderate increase in protein but a large reduction in energy from carbs and fat.   

While we need enough protein to meet our needs, our appetite for higher-protein foods turns off once we get our fill.  Minimally processed protein is a poor energy source because it has high dietary-induced thermogenesis.  In other words, your body must work harder to satisfy your everyday energy requirements.  For more on why this is, check out Oxidative Priority: The Key to Unlocking Your Fat Stores.

The frequency distribution chart below shows that the average protein % for our Optimisers is 32%. Not many people manage to sustain a very high protein protein intake above 50% for long.    

How Has Our Protein Intake Changed? 

Based on USDA Economic Research Service data, we constructed the chart below.  Here, we can see that the average protein intake in terms of per cent ranged from 10.5% in the 1930s after World War I to 13% of calories in 1977 when the first US Dietary Guidelines were released.  From then on, people tended to avoid red meat for fear of cholesterol and consumed more of the tasty food products made possible by Big Agriculture and food manufacturers.  

It’s worth noting that during the time that protein percentage has decreased over the past 50 years, the obesity epidemic has taken off.  

The following chart shows the change in calories from each macronutrient over the past hundred years or so.  Here, we can see that easily available energy from carbs AND fat has fuelled the obesity epidemic.  Interestingly, our protein intake has remained fairly stable throughout this time.  For more on other nutrition trends, check out How the Biggest Nutrition Trends Influence How We Eat Today. 

When it comes to absolute protein intake (in grams), most people struggle to eat very high amounts of it.  Optimisers tend to gravitate towards around 1.8 g/kg LBM per day.   

Eat Like The Animals shows how going from 15 to 13% of our total calories from protein is more than enough to explain our growing obesity epidemic.  A shift from 15 to 17% is more than enough to reverse obesity and diabetes over time.  

While this sounds simple, it’s hard to do because we find low-protein, fat-and-carb combo foods irresistible whenever they’re available.  Sadly, this lethal; mixture describes most of the ‘edibles’ in our modern food system, especially in the world of cheap, hyper-palatable, hyper-profitable junk food.

For more on finding your ideal protein intake, see Protein – Optimal vs Acceptable Macronutrient Distribution Range (AMDR)

The Plot Twist of Eat Like the Animals! 

In chapter eight, Eat Like the Animals gets a little confusing when they review their ‘mega mouse’ study (The Ratio of Macronutrients, Not Caloric Intake, Dictates Cardiometabolic Health, Aging, and Longevity in Ad Libitum-Fed Mice) co-written by 14 high-profile authors, including longevity and mTOR guru David Sinclair

I had a number of people ask me about this section after they had read this, so I thought it would be worth digging into the data a little further. 

In our previous article, Can Longevity Be Bought in a Bottle?  Thoughts on David Sinclair’s Lifespan, we discussed and analysed the conflicting goals of a low-protein, plant-based ‘longevity’ diet that also aims to optimise nutrient density and body composition.  

In summary, no human data has shown a positive relationship between protein restriction and long-term longevity.  On the one hand, eating anything to the point that you grow bigger than you need to is not ideal.  However, just because there are positive studies on protein restriction in yeast and worms does not mean that these theories automatically transfer to humans. 

Sadly, it seems that the fear of ageing induced by ‘too much protein’, and mTOR may have influenced this study.  

The mega mouse study was one of the most expensive nutritional experiments ever conducted.  It began with feeding 1000 mice a matrix of 30 different diets with varying energy densities, oscillating between high, medium, and low.  Their macronutrient contents also differed.  

The graphical summary of the study below shows that a high-protein, low-carb diet leads to a substantial decrease in food intake and adiposity.  This aligns with what we know from past human studies and our own satiety analysis.

But surprisingly, the researchers also concluded that the mice eating a high-protein diet had worse metabolic health and a shorter lifespan.  Meanwhile, the mice on a low-protein, high-carb diet were fatter but (apparently) had a longer lifespan and better metabolic health.

After the study was published, the University of Sydney released several statements and news pieces saying that high-protein diets may shorten a human’s lifespan… despite the study being performed on mice.  

So, what the…? 

This is not what I expected from the guys who developed the Protein Leverage Hypothesis!?!

Does Obesity Increase Human Longevity?

So, is a high-protein diet good for diabetes, or can a high-protein diet cause diabetes?  Does high dietary protein intake contribute to the risk of developing prediabetes and Type-2 Diabetes?  And does too much protein turn into sugar?

Before your mind starts racing, I have a question…  

Where do we see increased adiposity in humans improving metabolic health and lifespan?  



That’s right. 


Increased obesity is a significant risk factor for all-cause mortality (death of any cause) and almost every modern disease.  From diabetes to heart disease, hormone and fertility-related disorders, and even cancer, excess body fat and a dwindling muscle mass lies below almost every modern metabolic disease.

What we know about humans is that those who are leaner and have better metabolic health live longer and have fewer instances of disease.  Modern medicine knows this, and it’s why the first thing any doctor tells you to do is ‘eat healthy and lose weight’… although most of them don’t know how to get you there!

We can see this in a few (of the many) examples we’ve included below.  

In the following two charts, taken from Waist-to-height Ratio Is More Predictive of Years of Life Lost Than Body Mass Index, we see that a lower body mass index (BMI) or waist-to-height ratio aligns with a longer lifespan and greater longevity.  

Similarly, these next charts from Quantitative association between body mass index and the risk of cancer: A global Meta-analysis of prospective cohort studies: Obesity and cancer risk shows that leaner people are less likely to get cancer. 

This benefit is not infinite, and there is no need to be bigger or stronger at all costs.  However, we know that having a higher fat-free mass index (i.e., more muscle, lean body mass, or lean mass) aligns with greater longevity in humans (Genton et al., 2013).     

Being stronger aligns with more resilience as we age.  While lab mice die of old age in a cage, many humans die prematurely from conditions stemming from frailty and fragility and do not make it to old age.  Slips, falls, and broken bones are not uncommon, and many never leave the hospital system afterwards due to the many complications that follow.

Outside of theory, we don’t have much data on mTOR’s effects on humans.  mTOR regulates protein synthesis and cell growth, and its overactivity is often blamed for conditions like cancer. 

But similar to BMI, waist:height ratio, insulin, and IGF-1, it appears optimal does not lie at the extremes, as shown in the chart below.  On the right-hand end, we have obesity and all the negative implications of poor metabolic health.  However, on the lower end, we also have the risks of sarcopenia, frailty and reduced immunity related to being underweight. 

Digging Into the Data of Eat Like the Animals

After feeling bemused by the headlines that took off after the mega-mouse study, Dr Ted Naiman pointed me toward some interesting discussion around the study’s methodologies. 

The experiment started with 1000 mice on 30 different diets.  But if you read the supplemental materials, you learn that 143 mice on five low-protein diets were euthanised after 10 and 23 weeks because of weight loss, rectal prolapse, and failure to thrive.  

Initially, I was shocked that they would exclude data from the mice that died due to protein malnutrition in a study specifically set up to identify the relationship between protein intake and lifespan and then declare that a low-protein diet is optimal for human longevity. 

After initially publishing this review article, Simpson and Raubenheimer emailed me and noted:

The aim of the experiment was to test the relative effects of total energy intake vs. P:E ratio on lifespan in mice.  In order to do that, we decided to map out the viable diet space for mice—something that had not previously been done—then establish the effects of energy density vs. P:E ratio within the viable diet space.  

Here ‘viable’ has an objective and scientifically based meaning; it encompasses the range of diets that support development throughout the life cycle.  Death due to non-viable diets vs. death due to accelerated ageing on feasible diets are two very different things, and confusing these will lead to nonsense (e.g., concluding that low P shortens lifespan because a cohort of human children restricted to cardboard didn’t survive into old age). 

Our results showed that diets that combined very low energy density with very low P:E ratios (5% energy from P) were non-viable (as indeed they are for humans).  These diets did not support growth in weanling mice.  

Not only would including these diets in the analysis be inconsistent with the question our experiment addressed–equivalent to cardboard diets for children–but we were mandated under the terms of our ethics permitting us to cull those mice.

To dig a little deeper, I imported the data from the supplementary material into Excel and added the data from the mice who died prematurely.  The yellow rows are the mice that died of protein malnutrition and were excluded from the analysis.  

Before doing any whiz-banging data analysis, it’s helpful to look at the raw data.  Most importantly, the green row towards the bottom of the table shows that the mice that lived the longest consumed 42% protein.   

No, the mice on the highest-protein diet did not live the longest.  But who consumes 60% of their total calories from protein in the real world?  As our protein intake distribution charts from our Optimisers’ data showed, no free-living human gets 60% of their calories from protein for long!  

In the real world, we’re talking about getting humans to increase their protein intake slightly from an average of 12%.  

In nutrition and biology, optimal is rarely found at the extremes.  It’s much more useful to understand where you are now and how you need to modify your diet incrementally to move toward your goals. 

Macros vs Intake in Eat Like the Animals

Before we even dig further into the more controversial longevity data, let’s quickly look at what the data tells us about the relationship between our macro and calorie intakes.   

Protein vs Ad-Lib Calories in Eat Like the Animals

In line with the Protein Leverage Hypothesis and our satiety analysis, the first chart shows that mice ate less when fed ad-libitum diets with a higher protein per cent. 

The energy density of the diets range ranged from high (grey), medium (orange), and low (blue) energy.  Unsurprisingly, mice were able to eat more of the substantially energy-dense foods in the absence of protein, thus increasing calorie intake.  This also aligns with our Optimiser data that shows humans eat less when we consume a higher protein %. 

While energy density does influence how much we eat, it’s not the whole story.  For more detail, see Low Energy Density Foods and Recipes: Will They Help You Feel Full with Fewer Calories?

Carbohydrates vs Ad-Lib Calories in Eat Like the Animals

This next chart shows that mice ate less when their diet contained more carbohydrates.  However, it’s essential to consider that this may be interrelated with fat intake, which is more energy-dense and could contribute to this caloric increase.

It’s worth noting that the data from a thousand mice show a different outcome than our thirty-five thousand Optimisers.  While mice tend to eat less when they consume more carbohydrates, humans seem to eat less when they reduce carbohydrates from 40-50% to 10-20% of calories.  To the right of the chart, we can also see that we eat a little less if we push fat very low and increase carbohydrates to greater than 50% of calories. 

Check out Carbohydrates – Optimal vs Acceptable Macronutrient Distribution Range (AMDR for more guidance on finding your ideal carbohydrate intake.

Fat vs Ad-Lib Calories

Finally, this last chart shows that mice eating a higher fat % consumed more calories.  This is not surprising, considering fat is the most energy-dense macronutrient.   

Our data analysis from Optimisers also shows that humans eat more when our diet contains more energy from fat. 

Check out Fat – Optimal vs Acceptable Macronutrient Distribution Range (AMDR) for more guidance on finding your ideal fat intake.

Eat Like the Animals Take-Home Message… That Is, If You’re a Mouse

If you’re a mouse that wants to get lean and mean for beach season, you want less fat and more protein.  That said, it’s important to note that mice are not tiny humans.  

As this paper notes, the lab mice used in the mega-mouse study tend to do worse than humans on a high-fat diet. 

Our data from Optimisers suggests that humans tend to handle carbs OR fat just fine.  Reducing or increasing either fat or carbs will have a similar impact on satiety.  However, it’s the combination of carbs AND fat that makes us overeat.

Lifespan of Mice  

Things get more interesting when we look at the study’s lifespan data.  When you look at the charts below, see if you think it aligns with the key conclusion of their paper.  For convenience, I’ve included it in the screenshot below.   

Calories vs Lifespan in Eat Like the Animals

The following chart shows energy intake vs average lifespan.  The data point outliers at the bottom of the graph are those that died early from protein malnutrition.  

In the following chart, we’ve shown the same data.  However, we’ve removed the 143 mice that were euthanised to uncloud the data.  While there is still plenty of scatter, we see an optimal energy intake that is midrange. 

The outlier in the middle at the top with the longest lifespan—by a mile! —is the group of mice eating 42% protein!   

Severe energy deprivation is not good, but neither is too much energy.  Thus, there is a ‘goldilocks’ energy intake for mice (and humans).

Protein vs Lifespan in Eat Like the Animals

The following chart shows protein (in grams per day) vs lifespan.  When you include the 143 dead mice on the five failed low-protein diets, mice seem to do best on around six grams of protein per day.  However, the best outcome of any of the groups was seen on seven grams of protein per day, not a lower protein diet.

The following chart shows the protein intake vs lifespan data after removing the euthanised mice.  As you can see, there is a LOT of scatter and very low correlation!  Once you remove the mice who failed to thrive on a low-protein diet, there is NO relationship between protein intake and longevity.

With such a weak correlation, it’s bemusing that the conclusion published in the Sydney Morning Herald was that low protein, high carb diets can help us live longer.   

Perhaps ‘eat less protein’ might be an appropriate message for steroid-injecting bodybuilders living on egg whites and protein powder.  But I think it’s the wrong message to send to the general population, given most of these people already lack protein because of their heavily processed diets or follow some version of a plant-based or keto diet that shuns protein.  

Finally, the following charts show the data in terms of macronutrient percentages.  I have included separate trend lines for diets with low, medium, and high energy densities and one with all the data.  

The first plot of protein percentage vs lifespan has the strongest correlation of all the charts.  If you had to conclude from this noisy data (all points included), you might say that mice reach optimal longevity when consuming 30–40% of energy from protein.  

This also aligns with our analysis of the Optimisers data that a greater protein intake (up until about 50% protein) aligns with a greater nutrient density.  A very low-protein diet tends to be very low in essential vitamins, minerals, amino acids, and essential fatty acids.   But at the same time, it’s not easy to push past 40% protein for long. 

Check out Protein – Optimal vs Acceptable Macronutrient Distribution Range (AMDR) for more guidance on finding your ideal protein intake.

When Could ‘Too Much Protein’ Be Bad?

Can you get too much protein?  

Yes!  Eating too much of anything is not good. 

Is any free-living human at risk of getting ‘excess protein’?

No!  Highly unlikely! 

When it comes to humans—and mice—the first thing to remember is that body composition is king.  Even if you don’t want to be a jacked bodybuilder, having more lean mass and less fat is critical for metabolic health and long-term survival in the real world. 

If you have excess body fat, your insulin and blood glucose are higher, and your overall risk of dying of any cause increases! 

Body mass index, fasting blood sugars, and insulin levels across the day are closely tied to how much fat you hold in storage.  

Fasting blood glucose levels above 100 mg/dL (5.6 mmol/L) are correlated strongly with your risk of dying of all-cause mortality.  

If you want to preserve the protein in your body and deplete the stored fat and excess glucose, you need to ensure you eat enough protein while trying to reduce the fat and carbs in your diet.  For more on finding the right balance of protein vs energy, check out our article, Secrets of the Nutrient-Dense Protein-Sparing Modified Fast.

But the story changes as you run out of body fat to burn.  Protein is the most thermogenic macronutrient and is relatively labour-intrinsic to turn into usable fuel.  In other words, we burn the most energy turning it into usable fuel (ATP).  

Once your body fat levels are healthy, your fasting blood glucose is below 90 mg/dL (5.0 mmol/L), and you continue to eat lean protein, your body will have to work harder to convert it into usable fuel.  Thus, you may find yourself hungrier as your body seeks extra energy.  

Once you reach optimal body composition and fasting blood sugars, you should add some easily accessible energy from fat or (and) carbs to ensure your body doesn’t over-exert itself getting the energy it needs from protein.  

But until that point, you probably should lay off the fat and (or) carbs a little while still ensuring you get enough protein. 

How Do You Leverage Your Protein Intake?

There is no universal protein leverage diet that will work for everyone all the time. 

Depending on your body’s unique needs, you may require more protein—or less—to satisfy your body’s appetite and cravings than the person next to you.   

As a minimum, we recommend hitting the minimum daily protein shown in the table below.   This is based on 1.4 g/kg LBM and an ideal 15% body fat for men and 25% for women.  

height (cm)height (inches)female protein (g)male protein (g)

But to understand the protein intake that’s right for you, it’s worth taking the time to understand your current typical intake and then progressively adjusting your targets for the coming week to ensure you are moving towards your goals at a sustainable rate. 

This is the process we guide people through in our Macros Masterclass.  Over four weeks, we walk Optimisers through prioritising protein intake while dialling back their fat intake to find the best macronutrient ratios that lead to sustainable results without swinging to extremes. 

We usually find most people are already pretty close to their ideal macro intake.  They only need to make some minor tweaks to see consistent and sustainable results. 


If you carry more body fat than is healthy, you likely need to focus on consuming more energy from protein and other low-energy-dense, nutrient-dense foods. 

This will help you avoid diabetes, cancer, heart disease, neurodegeneration, and any other disease related to obesity.  

Once you achieve optimal body fat and fasting blood sugar levels, you can add back some easily accessible energy from fat and carbs.  

When it comes to protein, you should eat like the animals and follow your appetite for it!   But unfortunately, humans tend to reverse engineer the protein leverage hypothesis and manipulate our food environment to maximise energy intake and profit.   But with this understanding, we can reverse this and claim back our health. 


14 thoughts on “Eat Like the Animals: The Origins of the Protein Leverage Hypothesis”

  1. I think there’s a thumb on the scale for carbs and dead mice: the c57bl/6 mouse, according to The Jackson Laboratory is ‘susceptible to diet-induced obesity, type 2 diabetes, and atherosclerosis. The study demonstrated that the c57bl/6 mouse performed as expected.

    • seemed like a well-designed study if you wanted to prove that carbs were better than fat. they had to exclude the mice that died from protein malnutrition to paint protein as bad.

      • I believe the ‘plot twist’ comes from reliance on standard blood test information. Many people eating LCHF diets have bad cholesterol results, per blood tests. I believe the issue is the blood test standards were created based on people eating the Standard American Diet, and that there should be a difference in the interpretation of results based on diet. For instance, my total cholesterol numbers went up to very high levels as I adopted the LCHF diet. But my triglycerides:HDL ratio is very good at less than 1. However, many doctors stick to the traditional standards and try to push for statins based on another group of eaters. I’m in the process of gathering information for my PCP so she will understand my numbers don’t matter. I even had a Cardiac Calcium Exam, with a score of 1! Yet she’s still trying to push me to start statins. Yes, I know I could switch doctors, but in my area, it is very unlikely to find a doctor who knows this way of thinking, unless it’s a naturopathic practice, not covered by my insurance.

  2. Interesting that you do not mention autophagy Marty. Ron Rosedale pointed out that recycling your proteins decreases the need for dietary protein intake.

    In our continuing n=2 experiment, my wife and I have certainly noticed we get full very quickly on a small amount of dietary fat and proteins while being on a permanent 12 hours intermittent fasting regime.

    • autophagy is great, but the reality is we know very little about the minimum effective dose in humans. is it 12 hours? 2 day? 7 days? 40 days? what we do know though is that getting to optimal body composition, in terms of body fat, waist to height ratio, BMI etc are strongly correlated with longevity and decreased risk of all-cause mortality. see FAQ#19 and 56 in the DDF article here for more details.

  3. Marty, I don’t quite get your derogatory comment about the fear of mTor.

    Ron Rosedale has shown quite convincingly that mTor is the epigenetic energy sensor that flips the metabolism between the growth mode and the repair mode. Healthy longevity can only be achieved through cellular regeneration and repair and that is only possible by keeping mTor low.

  4. I am a 69 years old female and have been eating a strict carnivore diet since Oct of 2015. I did well on losing fat. Recently though I have gained about 25 pounds over the last year or so. I know I am eating when I’m not particularly hungry and I imagine that is what is causing the weight gain. I also love butter so maybe overdoing the fat. Any thoughts or suggestions on my getting back on track. Eating animal products only has made my compulsive overeating disappear and I have zero cravings so I don’t want to change my way of eating. Thanks!

    • Many people do well on a carnivore diet because they get plenty of bioavailable protein which helps with satiety. But the protein leverage hypothesis still applies to animal based products. It is possible to overdo added fat. We have a free nutrient dense carnivore food list, a free macro calculator and a nutirent dense meat book that you maybe interested in checking out on our resouce page here – , I have also written some articles on the pros and cons of carnivore that you may be interested in here –

  5. First, it’s outrageous the study data were manipulated and then false results were published in such a high-profile way—the opposite of serious, academic research! I hope people were fired.
    Thank you for revealing the facts around the study and providing the actual insights we should glean from it.

  6. Thank you Marty for your analysis, I was quite relieved to read it. I have been low carb / higher protein for 4 years but always like to keep an open mind so this book raised many doubts, it seemed legitimate. But when research “omits” data and “jumps to conclusions” I am happy to be a sceptic until the science proves otherwise

  7. I have an interesting thing going on with my body: if I eat too much fat (when doing keto), I break out into a rash on my right side–just in the armpit and shoulder areas. the exact same thing happens when I cut the fat and up my protein on protein sparing days (all while keeping carbs low). Now I think I see what’s going on–your chart just under the “”Why we love steak and chips” section illustrates it beautifully. I may have been swinging back and forth from one form of malnutrition to the other, and my body is trying to tell me this. I’m going to glean tips from this article to better get my macros back in line and avoid the rash (if at all possible). I haven’t signed up for Cronometer or the Nutrition Optimizer because I don’t know exactly who all would have access to my data, or what they’d do with it (beyond you). How do I know that data isn’t being sold out the back door?

    I don’t know what the researchers expected, since mice are herbivores. Using mice to judge the feasibility of a high-fat or high-protein diet for omnivore humans seems ludicrous at first take, and forcing them to eat outside their natural macros may be akin to animal abuse (I know, I know–without the research, how would we know?). But just once, I’d like to see a scientist try to feed mice a nice juicy steak, and see how far it would go. At the same time, I’d like to see more research into the health and disease aspects of eating grass-fed, pastured meats as opposed to CAFO-raised meats–the results should shut up the naysayers out there that swear up and down that “meat consumption” in general is going to ruin health and the planet. Without adequate bio-available protein, we’d turn into a nation (or world) of people who have fallen and can’t get up (read: sarcopenia).

  8. Re: the link to your article about David Sinclair and Can Longevity Be Bought in a Bottle? (since comments on the article are now closed–I must’ve missed that one)

    Both David and Dr. Longo carry the idea that reducing methionine intake (through reduction of meat intake) plays a role in longevity. I have a challenge to that: food allergies. Methionine, B6, DAO, and other deficiencies all play a role in the reactions and stopping them. So if you are limiting or avoiding meat for LONGEVITY reasons, but setting off reactions to other foods by doing so, are you really likely to live longer…or just live longer with a hoard of EpiPens nearby at all times?

    Judging by your article there, it seems the whole human longevity field is nothing more than a huge fund-raising scheme, since the same “longevity chemicals” or their precursors can be had through proper nutrition. They promise longevity in a bottle, sell it for outrageous prices, get people to buy them, and the money either goes into a pocket somewhere (probably some yacht-dwelling denizen) or back into “research” to come out with yet another “breakthrough” substance in pill form, and the whole cycle continues indefinitely. Even Aubrey DeGray of Britain was asked by his government to stick to longevity information that the average reader could use today, and not wander into regeneration/singularity territory.

    Longevity comes down to a few things: genetics, lifestyle, and accident/illness avoidance. Genetics and lifestyle can be dealt with through generations of proper nutrition. Illness/accident avoidance can be dealt with through a combination of nutrition (to fuel the brain (for judgement, vision, hearing, etc.) and through appropriate vaccination. It’s just too bad we have to rely on each other or kill switches to avoid other types of accidents–how do you convince others that eating the right foods can literally save lives, and then GET THEM TO DO IT…then KEEP DOING IT…for generations?

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