What is the protein leverage hypothesis?

It’s the idea that overeating and obesity happen when the proportion of protein in the diet is too low. Because humans need a consistent amount of protein in their diet for their bodies to function properly, they will eat as much food as they can to reach the necessary amount of protein. In an environment with a bunch of processed junk food that is low in protein but high in carbohydrates and fat, humans will overeat because their bodies remain hungry for protein.

The “leverage” part refers to the power of protein in the diet to either increase or decrease obesity. As the percentage of protein in the diet goes up (and thus the percentage of carbs and fat go down), the total calorie intake will naturally go down because the body will not be hungry and searching for protein. Vice-a-versa would hold as well. As protein percentage in the diet goes down, total calorie intake will go up as the body searches for adequate protein.

Where did the protein leverage hypothesis come from?

In 2005, two biologists at Oxford University published a paper in the journal Obesity Review where they presented their protein leverage hypothesis. They argued that as obesity increased across the world in the previous decades, the amount of protein in the diet remained stable. It has only been fat and carbohydrate that have increased.  

They showed through lab studies and large observational studies that when protein makes up a smaller percentage of meals, people are hungrier and thus overeat. They argued that if people can eat high-protein meals, they won’t be as hungry and thus will more easily reduce their food intake. Their hypothesis has been supported by randomized controlled trials like this and this. And they went on to write a popular science book on this topic, published in 2020, called Eat Like the Animals.

Why should parents care about the protein leverage hypothesis?

Childhood overweight and obesity have steadily risen over the last 50 years. In 1971, 5% of children 2-19 were obese; today, over 19% of kids are obese. For adults it’s worse: from 1970 to today, the percentage of Americans who measured as obese went from 15% to nearly 40%.

Overweight and metabolic illnesses affect nearly every family in the developed world. The protein leverage hypothesis tells us why. It’s not that people have become gluttonous and irresponsible. It’s that our food environment has become filled with foods that are low in protein and high in carbohydrates and fat. These foods leave our bodies hungry and searching for more protein--and so we eat more than we would if we were getting adequate protein.

As parents, if we can shift our family's meals toward higher protein content, we can more easily manage the amount we eat. We don’t need to worry about counting calories when our bodies are feeling full and satisfied after eating high-protein meals.

How can parents use the protein leverage hypothesis in their daily lives?

There are two approaches parents can take, and they can be combined. First, look for ways to increase protein in each meal and especially snacks. This can be done in pretty conventional ways by just increasing normal sources of protein: meat, fish, cheese, nuts, and beans.

The second approach is to reduce the meals and snacks that are high carb + fat. This basically refers to all junk food: candy, desserts, chips, fries, pizza, pasta, bagels, muffins, etc.

The protein leverage hypothesis requires some calculating if you really want to follow their prescription. But for busy parents, simply cutting out unnecessary carbs and adding extra protein is an easy way to get on the right side of protein leverage.

The vast majority of the Yes Collective recipes follow this high-protein, low-carb philosophy with the goal of making it easy for kids and parents to eat delicious foods until they’re full, and not worry about limiting portions and counting calories.

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