Protein Leverage Hypothesis: Key to Optimal Nutrition and Satiety

Discover the secret to sustainable weight loss with the Protein Leverage Hypothesis. This groundbreaking revolutionary reveals how the percentage of protein in our diet impacts appetite regulation, nutrient density, and overall metabolic health.

By prioritising dietary protein, you can achieve a better satiety response and balance your energy intake. Discover how optimising your macronutrient balance can transform your weight management journey.

Dive into the science behind protein leverage theory and learn practical strategies for enhancing your diet with high-quality protein sources for optimal health outcomes.

What Is the Protein Leverage Hypothesis?

Your innate appetite ensures you get the right balance of nutrients and energy from available food. Although protein is a small percentage of your diet, it is critical to survival, prompting an intense craving.

The Protein Leverage Hypothesis suggests that in a low-protein environment, we overconsume energy to meet protein needs, leading to weight gain. This theory highlights the importance of protein intake and nutrient density for regulating appetite and achieving metabolic health.

The critical thing to note is that it doesn’t take a significant shift in your current protein % to leverage a substantial change in energy intake.  You only need to dial back your carbs and fat while prioritising protein.  

As highlighted by the “unbalanced” scenario in the figure below, increasing your protein percentage too much will lead to excessive hunger because your overall energy intake drops so much. Finding the balance of protein vs. energy is crucial to achieving consistent and sustainable weight loss.

What is the “Leverage” in Protein Leverage? 

A lever uses a slight movement in one parameter to produce a significant change in engineering. In finance, leverage is borrowed money that costs little and can significantly increase an investment’s gains or losses. Similarly, in the Protein Leverage Hypothesis, protein is a powerful force influencing our energy intake from fat and carbs, helping us manage weight effectively.

Rather than jumping from low to high protein extremes, you only need to nudge your protein percentage to increase satiety and lose weight sustainably. Conversely, growing children or lean athletes may benefit from a lower protein percentage to reduce satiety and allow them to consume more energy. 

How Does the Protein Leverage Hypothesis Work? 

Protein leverage has been observed in a wide range of living organisms, from slime to apes and humans. This phenomenon demonstrates that protein intake influences appetite regulation and energy balance, leading to significant changes in body composition and metabolic health.

Free-living animals in the wild use their keen sense of smell and taste to seek out the nutrients they need.  If they only have access to low-protein foods, they experience excessive hunger (hyperphagia) in the pursuit of adequate protein.   

Did you know that crickets become cannibals if they can’t get protein?  Crickets march across the landscape for food and keep ahead of the hungry crickets behind them.

The amino acids that make up protein are essential to life and some of the most critical nutrients for human function. These nutrients synthesize, maintain, and rebuild our DNA, organs, muscles, bone, hair, skin, and nails. They also help us detoxify and produce various enzymes, neurotransmitters, and hormones that catalyze bodily function.

While we can recycle some protein, it isn’t very efficient.  Hence, we need to eat enough of it.  Our protein requirements increase if we are more active, stressed, losing weight, growing, or healing. 

The Satiety Response to Protein

When we’re not getting enough protein, we crave high-protein foods. But once we exceed the minimum amount, we experience sensory-specific satiety and no longer crave protein-rich foods.

Our satiety analysis of more than a million days of data shows that people who consume a diet with a higher protein percentage tend to consume much less energy than those with a bliss point protein intake of 12.5%. This underscores the critical role of protein leverage in appetite regulation and weight management.

The chart below shows the distribution of protein % in our data. While some people manage to achieve a very high percentage of their diet from protein, most of us crave more energy from fat and/or carbohydrates and gravitate back to the bliss point that aligns with consuming the most energy.

Who Developed the Protein Leverage Hypothesis?

In 2005, Professors David Raubenheimer and Stephen Simpson of the University of Sydney published Obesity: The Protein Leverage Hypothesis.  In this original paper, they proposed that protein dilution in our modern processed food environment elegantly explains the obesity epidemic. 

This prolific duo has worked together for decades, publishing hundreds of papers since David was Stephen’s PhD student at Oxford University. 

For a quick overview of the Protein Leverage Hypothesis, I highly recommend this 15-minute presentation by Professor Simpson to the Royal Society scientific meeting on the Causes of obesity: theories, conjectures and evidence (starts at 37 minutes).

You can watch my interview with David and Stephen for a deeper dive into the origins and practicalities of protein leverage.

History of the Protein Leverage Hypothesis

After studying insects and animals for decades, in the early 2000s, Raubenheimer and Simpson wanted to apply what they knew from studying nutrition, ecology, and etymology in animals and apply it to the runaway obesity epidemic. 

After noting that it had begun in the last fifty years, they felt that something environmental must be at play.  This made them wonder, ‘What changed around us that allowed us to eat so much energy?’  The chart below shows that calorie intake and obesity increased after the Second Agricultural Revolution in the 1960s. 

After studying how various insects and animals innately choose a balanced diet from a seemingly random selection of foods, they wondered whether humans could do the same in our modern environment. As we can see in the chart below, our protein intake has increased marginally since the 1960s. In contrast, fat and carbohydrates have increased significantly. 

Their analysis showed that the appetite of various organisms—including humans—increases significantly when the percentage of total calories from protein increases only marginally. In addition, a slight change in protein percentage was enough to explain the significant increase in energy intake from carbs and fat.  For example, as shown in the chart below, reducing protein from 14% to 12.5% aligns with a 14% increase in energy from carbs and fat. 

Raubenheimer and Simpson concluded that it’s not one single nutrient that influences obesity but rather the balance of protein vs energy.  Rather than fat OR carbs, fat AND carbs dilute the protein in our food system and drive us to eat more. 

Ominously, when we look at the changes in the food system using data from the USDA Economic Research Service, we see that protein % has decreased from around 13% to less than 12% since 1977.   This seemingly minor decrease in protein % is enough to explain the accompanying growth in obesity.

Protein is the Most Expensive Macronutrient

Beyond the mathematical and physical quantifications of the obesity epidemic, Raubenheimer and Simpson used socioeconomic and biological reasoning to complete their theory. Protein is the most necessary macronutrient for human life; amino acids partake in nearly every bodily process, including growth and regeneration, and comprise a significant proportion of our body, second only to water. 

Unfortunately, protein is the most expensive macronutrient.  Hence, lower-cost, high-profit-margin foods made from industrial seed oils and subsidised grains are more heavily marketed, and consumers gravitate towards them due to their palatability and low cost.  Hence, those living in lower-income households might find themselves drawn to less-expensive fat-and-carb combo foods for price and pleasure.

Protein Leverage is Not About MORE Protein

When most people first hear Protein Leverage, they first respond to eating more protein.  However, because protein typically comes with fat, merely increasing protein tends to lead to an increase in energy intake (as shown in the chart below).  Eating more butter, bacon, and nuts won’t help increase your protein %. 

Instead, to implement the power of the Protein Leverage, you need to focus on protein % or per cent of total calories from protein.  Your protein intake, carbs, and fat influence your protein %.  Hence, optimising your protein % requires you to dial back your carbs and fat while prioritising protein. 

The figure below (from Raubenheimer and Simpson, 2019) shows a compilation of protein percentage vs. energy intake data from human studies. Note that protein intake (in grams) increases marginally as we increase protein percentage while total energy drops significantly. 

We see a similar trend in our data analysis.  As we increase protein %, absolute protein (in grams) increases marginally while total calories decrease significantly. 

The Other Nutrients Matter

In 2019, Raubenheimer and Simpson published a follow-up paper, Protein Leverage: Theoretical Foundations and Ten Points of Clarification, to clarify several common misconceptions about the Protein Leverage Hypothesis. 

One of their points highlighted that Protein Leverage isn’t independent of food quality and micronutrient content.  The macronutrient protein comprises twenty amino acids that all play distinct roles in our body.  The chart below shows that getting more of each essential amino acid per calorie aligns with consuming fewer calories. 

But it’s not just protein or amino acids.  Higher protein foods also come packaged with other essential nutrients.  Minerals and vitamins also show a unique satiety response, meaning we consume fewer calories when we pack more of them into our food. 

Our analysis shows that up to around 50%, protein and nutrient density are closely correlated.  So, if you’re getting your protein from whole foods, you will also get plenty of the other nutrients clustered with protein.  So, protein leverage may not be due to protein but rather the nutrients that tend to be packaged in higher protein foods.

There is No One Size Fits All Protein %

Raubenheimer and Simpson also highlighted that a person’s protein target is not static. While everyone wants a simple number to aim for, there is no one-size-fits-all protein target. Protein requirements vary depending on life stage and activity levels. 

For example, older people need less energy and thus a higher protein % to get adequate protein.  While you may think that the young bros need more protein, we often see older women thriving on the highest protein percentages in our programs. 

Protein % and Insulin Resistance

People who are obese are often insulin resistant, which leads to more of the protein they consume being converted to glucose (via gluconeogenesis).   In their 2005 paper, Raubenheimer and Simpson highlight that increasing obesity and diabetes could explain why absolute protein intake has increased. 

Because more protein is converted to glucose if there is inadequate insulin, people who are insulin resistant tend to crave more protein to maintain the protein in their body.  Hence, if you’re insulin resistant, it’s even more important to prioritise protein and dial back energy from fat and carbs to lose weight and restore insulin sensitivity. 

For more details, see Macros to Reverse Insulin Resistance and Achieve Optimal Health.

Protein Leverage and Menopause

In their recent paper, Weight Gain during the Menopause Transition: Evidence for a Mechanism Dependent on Protein Leverage, Raubenheimer and Simpson elegantly addressed menopausal weight gain through the lens of protein leverage.   

To summarise:

• As women age, a reduction in estrogen and high follicle-stimulating hormone (FSH) and increased anabolic and insulin resistance lead to a loss of lean mass. While anabolic and insulin resistance occurs in men, menopause accelerates this process in females. 
• Our bodies seek more protein to compensate for muscle loss by eliciting cravings.
• Activity levels often also decrease as we age, so we require less energy from food. 
• If we don’t change our diets during this transition, we will consume more food to get the required protein and gain weight. 

For more details, see Menopausal Weight Gain: The Problem and Solution Explained.

Protein % and Low Carb Diets

As we increase protein %, energy from fat and carbs is reduced.  If your blood glucose is normal, it doesn’t matter if you tend to get more energy from fat or carbs.   

Because we can produce glucose from protein via gluconeogenesis, carbohydrate is not technically an essential macronutrient.  However, if you’re on a lower-carb diet, you may need to prioritise even more protein to compensate for the protein lost to glucose via gluconeogenesis and prevent the loss of your precious lean muscle mass. 

As shown in the chart below from our satiety analysis, a lower-carb diet aligns with greater satiety. However, zero carb is not necessarily better than lower carb. Cutting carbs to very low levels tends to exclude low energy density, non-starchy vegetables, which have a complementary nutrient profile to many high-protein foods. This leads people to overconsume energy-dense, low-satiety fat.

What Happens if You Push Your Protein % Too High?

In my podcast interview, Professors Raubenheimer and Simpson emphasised that they don’t advocate for high-protein diets. Instead, they see increasing protein percentage as a short-term ‘therapeutic intervention’. They also noted that, given that most of the population is overweight, most people would benefit from an increase in their protein percentage until they reach a healthy body weight.

Again, to achieve long-term success, it’s critical to find the balance of protein vs energy that allows you to make sustainable progress.  Because there is a limit to how much fat your body can liberate daily, it also needs some energy in your diet. 

In our Macros Masterclass, we find most people don’t thrive for long when they push their protein intake above 40-50%. After a few days, their cravings for energy from fat and carbs become excessive, and they find themselves in a rebound binge with a dysregulated appetite. Hence, it’s best to gradually ratchet up your protein intake by dialling back fat and/or carbs, as we do in our Macros Masterclass.

Although a short-term protein-sparing modified fast can help you shed a few extra pounds in an emergency (e.g., before surgery or an event like a bodybuilding competition), it is not ideal or sustainable over the long term.   

Instead of jumping to extremes, the best way to implement protein leverage is to progressively incorporate more protein-rich foods. This will automatically decrease your cravings for energy-dense, low-satiety, nutrient-poor foods that we often feel addicted to.

Summary

• The Protein Leverage Hypothesis explains how the proportion of dietary protein influences overall energy intake and appetite regulation.
• A higher protein % can reduce calorie consumption by enhancing satiety and balancing macronutrient intake.
• This concept suggests that increasing dietary protein can aid in weight management and improve metabolic health.
• By understanding and applying protein leverage, individuals can optimize their diet for better health outcomes and sustainable weight loss.

We’d Love to Hear From You!

How has increasing your dietary protein impacted your weight management and overall health? Share your experiences, tips, and questions in the comments below.

More

• Eat Like the Animals: The Origins of the Protein Leverage Hypothesis
• Protein Leverage | Professors Stephen Simpson and David Raubenheimer
• How Much Protein Should I Eat to Lose Weight?
• Protein to Energy Ratio (P:E) vs Protein Percentage (%)
• Diet Quality and Weight Loss: A Deep Dive
• Protein – Optimal vs Acceptable Macronutrient Distribution Range (AMDR)
• Macros Masterclass