Prioritize Your Protein

The Protein Leverage Hypothesis

Photo by 青 晨 on Unsplash

I have previously written about the importance of protein and its’ critical role in building and maintaining muscle mass, especially as you age. Today, I’ll focus on protein's role in reducing cravings to maintain or improve body composition.

The protein leverage hypothesis provides a glimpse of how vital adequate protein intake is to maintain a healthy diet without giving in to sugary snacks, extra calories, and weight gain.

A small yet eye-opening study from Australia demonstrated the powerful effects protein has on overall food consumption and the potential adverse effects that come with eating too little protein (1). Researchers divided 22 healthy lean subjects into three different groups. These groups were then subjected to four days of in-house dietary manipulation, which means they were shut in the lab for four days, and all their food was provided. All their meals and snacks were weighed and meticulously tracked as to how many calories, grams of protein, fat, and carbohydrates were consumed. Hunger ratings were tracked as well. Subjects were allowed to eat ad libitum, which means they could eat as much or as little as they wanted. The diets were composed of the following:

Group One Diet: 10% protein, 60% carb, 30% fat.

Group Two Diet: 15% protein, 55% carb, 30% fat.

Group Three Diet: 25% protein, 45% carb, 30% fat

Every subject stayed in the lab for four days, ate one of the above diets, took a week off, then returned and repeated the four days under a different diet until they completed each of the three other diets. Furthermore, the food provided was made to look as similar as possible so the subjects wouldn’t know which diet they were receiving. Have a look for yourself. Could you tell the difference between these meals?

The Big Reveal

This is where the power of protein is evident. The 10% protein group consumed an average of 260 more calories per day than the 15% or 25% groups. That’s 1,820 extra calories per week and a 7,280-calorie surplus over a month. This is a path to gaining over a pound a month! Most likely not in the form of healthy lean muscle tissue. Now, this is only one small study, but the results are compelling. According to the protein leverage hypothesis, eating at least 15% of calories from protein can help prevent overeating and, therefore, weight gain. Here’s how the percentages look as numbers.

The 10% protein group ate about 66 grams of protein per day

The 15% group ate 85 grams

The 25% group ate 138 grams

To put those numbers into perspective, the recommended daily allowance (RDA) for sedentary adults is .8 grams per kilogram of body weight, which comes out to 60 grams of protein per day for a 165-pound sedentary person, even less than the amount that was consumed in the 10% protein group! Athletes and those who regularly exercise require even more protein to recover from activity and maintain and build muscle mass. According to the protein leverage hypothesis, this is a woeful amount that could potentially lead to excess calorie consumption and weight gain, not to mention the negative consequences in performance an athlete or weight lifter might see if they under-consume.

My Takeaways

Even before reading this study, I’ve been an advocate for a high-protein diet, and this only reinforces that idea. Eating a minimum of 15% calories from protein is a reasonable target for sedentary people, and 20% to 25% for those who exercise regularly. Another good rule of thumb for athletes and active people is 1 gram of protein per pound of body weight. This can be challenging to achieve, but even if you fall short, you’ll still be well ahead of most people and likely eat enough to support your activity.

Reference

1. Gosby, et al. Testing Protein Leverage in Lean Humans: A Randomised
   Controlled Experimental Study, Plos One.