Wild animals don’t need nutritional guides, and the only obese animals are humans and our pets.

As we saw in an old article, a multitude of sensors Internal help us determine the nutrients we need at all times and the optimal amount of each of them.

One of these sensors indicates, for example, the adequate amount of protein, making us keep eating until you reach that requirement.

The current low-protein nutritional recommendations, along with the increase in ultra-processed foods (low in protein and fiber), have contributed to the current obesity epidemic because it costs us so much to lose weight.

In this article we explain one of the reasons: protein leverage, and we give some tips to reap the benefits of this macronutrient.

The protein leverage hypothesis

Initial studies were conducted in insects. The researchers found that the lobsters ate more or less calories depending on the availability of protein (study, study). If they were fed with feed rich in protein, they would eat less. If they used feed rich in carbohydrate they would eat more.

The caloric intake of lobsters rises when they eat a low protein diet

They repeated this experiment on mice (study), chickens (study), cats (study, study) and different species of apes (study, detail). In all cases they observed the same results: the higher the protein intake, the less fat accumulation.

The conclusion of these investigations is that protein is an important appetite regulating lever, hence it was called for this purpose “Protein leverage hypothesis” (detail, detail, detail).

Protein and human appetite

The next step was to test this hypothesis in humans. Does the protein produce the same effect in our case? Everything points to yes (study, study).

A study analyzed the evolution of the intake of the three macronutrients (protein, carbohydrate and fat) between 1971 and 2006. It concluded that, indeed, protein reductions are associated with higher caloric intake.

The higher the protein intake, the lower the total caloric intake. Source: https://pubmed.ncbi.nlm.nih.gov/31339001/

But finding associations is not enough to validate a hypothesis, we must test it experimentally.

That is precisely what another more recent study did, exposing its participants to similar menus but with different percentages of protein. It was found that by offering them menus with 10% protein they ingested a 12% more calories that if they used menus with 15% or 25% protein.

Later studies confirm that this is fulfilled rule nutritional both in thin and obese people (detail, study).

Protein and obesity

Both fats and carbohydrates have been (unfairly) blamed for the obesity epidemic. However, understanding the importance that our body assigns to protein, we might think that diets low in this macronutrient have contributed more to the obesity problem.

Official recommendations place the recommended protein intake at 0.8 g / kg per day, a value clearly less than optimal (detail, detail, detail).

In the last decades, the percentage of calories from protein has been slightly reduced. And precisely because of its leverage effect, even a small reduction in protein can significantly increase total calorie intake (detail, study).

As if this were not enough, people with insulin resistance have a elevated gluconeogenesis, converting more amino acids into glucose even in the presence of insulin (detail). This greater loss of amino acids could raise your protein requirements, and if they are not covered it will promote a higher calorie intake.


This protein leverage perfectly complements the proteinostat concept we saw in a previous article. By losing muscle mass our appetite increases, as an attempt by the body to regain lost protein.

This, in turn, would explain part of the rebound effect that we see in those who lose more muscle mass when trying to lose weight.

Practical recommendations

Moving from theory to practice, I propose these recommendations:

  1. Get enough protein, between 1.5 and 2 g / kg per day. It will not only help you lose more weight (study, study, study), but also reduce the rebound effect afterwards (study, study, study). If you are overweight, do the calculation regarding your target weight.
  2. Includes a good source of protein in your breakfast (25-40 g of protein). Many studies confirm that including more protein in the first meal of the day reduces appetite and total caloric intake (study, study, study, study). Some examples of breakfast.
  3. Eat more fiber. Along with protein, fiber is the other component of the diet that generates more satiety. The best source of fiber is vegetables, but it also includes fruit and legumes (a good combination of protein and fiber).
  4. Limit ultra-processed products. These products are designed to bypass all our satiety mechanisms, by minimizing, for example, their fiber and protein intake. Reducing protein lowers the cost of these products and makes us increase their consumption: double benefit for the food industry, double damage for us.
  5. Avoid muscle loss if you diet. Low-calorie diets often cause muscle loss, and this increases the subsequent rebound due to the effect of the proteinostat. Strength training is essential to avoid muscle loss.

More is better, up to a point

Many people eat less protein than they should but, from a certain point, more is not better.

On the one hand, once the required protein is covered, its satiating effect is reduced (study).

On the other hand, animal studies indicate that raising protein excessively shortens life (study, study). Protein increases the rate at which animals develop and reproduce, but they pay a price for it. Investing more resources in growth and reproduction limits the resources available for regeneration processes.

As we saw in this article, we must strike the right balance between two key metabolic pathways: mTOR and AMPK.

Both growth and regeneration processes are important, but they must be balanced

Protein raises, for example, IGF-1, an anabolic hormone that helps us build strength and muscle (study, study), and both strength and muscle are associated with greater longevity (study, study, study, study).

Even if you develop cancer, muscle mass reduces its lethality (study). As if this were not enough, IGF-1 preserves bone health (study) and facilitates fat loss (study).

However, too much IGF-1 can be problematic, for example raising the risk of cancer (study, study, study, study). We therefore seek to take advantage of all the benefits that protein provides but avoiding its possible harmful effects.

If we talk about mortality, It is as bad to have low IGF-1 levels as it is to be very high. According to this meta-analysis, the relationship between IGF-1 levels and mortality is U-shaped, and people with low IGF-1 have higher mortality than those with higher levels.

Some recommendations to take advantage of the good in protein and mitigate the bad:

  • Train strength. If your muscles demand IGF-1 to grow, there will be less available to feed cancer cells.
  • Cycle protein. If there is a history of cancer in your family, try cycling protein, consuming the recommended levels on the days you train and reducing it when you rest.
  • Do intermittent fasts. Autophagy recycles damaged proteins and strengthens the immune system, preventing various diseases. And there is no problem in concentrating the protein in a smaller feeding window (detail).
  • Broken proteins. In many cases the problem is not an excess of protein, but an amino acid imbalance. Raise for example the glycine consumption (improving the methionine / glycine ratio) could extend the life (detail).
  • Do a ketosis cycle, with interesting properties against certain tumors (more detail).

Summary and conclusions

Protein plays a central role in our biology. Not only is it the main component of our muscles and organs, it is also almost all biological processes require the intervention of some protein. It is no accident that our genes code for proteins, not fats or carbohydrates.

For this reason we have mechanisms that regulate our appetite for protein to ensure we eat enough of this macronutrient. Low-protein nutritional recommendations and the rise of ultra-processed foods (low in protein and fiber) make us overeat, contributing to obesity.

Raising your protein intake, without going overboard, is a simple strategy to lose weight more easily and retain muscle mass.