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Researchers say protein can help curb hunger and reduce the risk of obesity. Igor Alecsander/Getty Images
  • Protein leverage is a theory about the body’s need for protein as a driver of appetite.
  • Researchers say it could be one of many contributing factors to the rise of obesity rates in recent decades.
  • Experts point out that the protein leverage hypothesis still requires more extensive study.

It is well established that obesity is an increasingly prevalent condition and one with far-reaching consequences for public health.

The World Health Organization (WHO) states that being overweight or obese resulted in more than 4 million deaths in 2017 and that the rates of these conditions among children and adolescents have more than quadrupled since 1975.

While the reasons for this epidemic are many, a review article recently published by Philosophical Transactions of the Royal Society B focuses on one of the more recent theories around the causes of obesity: the “protein leverage hypothesis.”

The food you eat provides you with energy in the form of calories.

There are three basic forms that these calories can take: carbohydrates, fats, and protein.

The protein leverage hypothesis essentially proposes that when you don’t consume enough protein you’ll feel hungry, even if you’re getting calories from other sources.

Megan Wroe, a wellness manager and registered dietitian at the Wellness Center of Providence St. Jude Medical Center in California, told Medical News Today there is some validity to the theory.

“Basically, when you don’t eat enough calories from protein in comparison to calories from carbs and fat, you end up eating more calories in an attempt to meet those minimum protein requirements and can often end up over-eating in general,” she explained.

The relevance of protein leverage tends to be increased in highly industrialized areas of the world, including the United States, where processed foods high in sugar (a carbohydrate) and fat are often more affordable and readily available than fresh foods.

“Eating a diet high in these processed foods can lead to a low intake of protein compared to carbs and fats, creating a lower than optimal protein intake. According to protein leverage theory, this then drives over-eating in [an] attempt to meet protein needs and may be an explanation for the obesity epidemic in the United States.”

— Megan Wroe, registered dietitian

In theory, protein leverage could be a useful concept both as a tool and as a potentially avoidable obstacle in managing weight loss and maintaining a healthy weight.

For example, by intentionally consuming protein, you might be able to avoid feelings of hunger that could otherwise lead to overeating.

Jordan Hill, lead registered dietitian with Top Nutrition Coaching, told MNT there are some ways to incorporate this theory into your daily diet.

“One could prevent [protein leverage] from contributing to obesity by prioritizing protein-rich foods at meal and snack times, aiming for balanced meals, staying hydrated, and managing portion sizes,” she explained.

“In addition to those strategies, when eating grains, choosing ones that are whole grains will increase the protein and fiber content,” Hill added.

This advice might help you maintain a healthy weight or avoid weight again, but how might protein leverage be a factor if you’re trying to lose weight?

“Losing weight means cutting calories, and if those calories come from protein then that person may very well end up eating more and therefore curb their weight loss,” said Wroe.

However, this doesn’t mean that protein should be your exclusive source of caloric intake either as this could lead to other negative health consequences.

“It’s important to note that carbohydrates and fats play unique roles in the body and are still essential nutrients to lead a healthy lifestyle. Aiming for balance and moderation among the three macronutrients is recommended, and working with a registered dietitian can help individuals discover what an appropriate amount of each nutrient for them looks like.”

— Jordan Hill, registered dietitian

The review paper notes that there is no one single cause of obesity.

The authors say that protein leverage hypothesis is only one potential factor among others that range from the genetic to the behavioral, cultural, and even geopolitical.

“There is never one answer to eating concerns, but protein is a critical nutrient and very directly related to satiety, strength, immune health, and healthy weight; so prioritizing protein at meals and snacks is a good idea for many reasons,” said Wroe.

But protein leverage itself can be complex, as protein requirements can be different from person to person and even vary over your life.

“All nutrient requirements change as we age or go through various stages of life, such as having a baby, being an athlete, or going through surgery,” said Wroe.

Health conditions such as diabetes can also be interrelated to protein needs and obesity as can developmental milestones.

“Infants, children, and adolescents tend to require relatively high protein to support their growth and development. As folks enter adulthood, that protein requirement stabilizes in most cases,” Hill said. “And as a person enters older adulthood, they have slightly increased protein needs due to age-related muscle loss (sarcopenia).”

Of course, the protein leverage hypothesis is just that — a hypothesis.

It’s important to note that this new review was written by the same two authors who originally formalized the protein leverage hypothesis in 2005.

“Since then, the concept of protein leverage has gained attention in the field of nutrition and has been the subject of further research and discussion. However, it’s not necessarily universally accepted or considered to be a well-established concept and still needs to be researched more,” said Hill.

In this most recent work, the authors state that, “The global rise in obesity is both among the simplest and most complex of issues in public health.”

But some experts take issue with this characterization.

“It’s not simple by any means. It’s a complex medical disease with numerous contributors’ factors, including controllable and uncontrollable contributors. This article works to oversimplify the ‘cause’ of obesity,” Dr. Amanda Velazquez, the director of Obesity Medicine at the Center for Weight Management and Metabolic Health at Cedars Sinai Medical Center in Los Angeles, told MNT

“The protein leverage hypothesis is an educated guess,” Dr. Velazquez said. “It has not been studied sufficiently to say that this hypothesis is a major contributor [of over-eating].”