Going on a Diet? Eat More Protein While Cutting Calories

How much protein can you eat and still lose weight?

By Michael Ormsbee, PhDFlorida State University
Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily

We often hear that we should eat less if we want to lose weight. According to Professor Ormsbee, though, there’s one thing we should consume more of, and that’s protein.

Variety of protein rich foods
During severe cut-backs in caloric intake to loose a large amount of weight, muscle mass is preserved by including high levels of protein in the diet. Photo by Oleksandra Naumenko / Shutterstock

Dieting and Protein

If you go on a diet with the intention of losing weight, you might want to consider adding more protein to your diet. When people start a diet or purposefully eat less food, one of the major risks is losing muscle mass.

While you will lose body weight, you may also lose a lot of muscle. This impacts your body composition in the long run because having muscle mass helps you to burn calories, stay active, and be healthy. 

Research indicates that it is possible to preserve muscle mass and decrease fat mass even with severe caloric restriction. To accomplish this, you most likely need to consume more protein than you are typically used to.

Professor Ormsbee and his team conducted a research study in which class 3 obese people were all put on an extremely low-calorie diet at 800 calories per day, which was medically mandated due to the severity of their obesity. When the researchers added 12 weeks of resistance training and much more protein for some of these participants, they still lost a lot of weight. 

However, they were able to maintain a greater amount of muscle mass compared to the people who did not incorporate resistance exercise and a high-protein diet. This study implies that even when we are in a severe calorie deficit, eating more protein and lifting weights can help prevent significant losses in muscle mass.

The ability to maintain muscle while losing fat is one way to rescue our resting metabolism. This means that you just increased your ability to fight weight regain, or putting all of the weight back on, as is typical after the diet stops or changes. 

Protein Benefits for Average Weight

However, this protein benefit doesn’t only apply to those on medically directed extreme weight loss plans and people who are severely obese. It applies to anyone trying to lose body fat. When lowering your calorie intake in an attempt to lose body fat, you increase your chances of success by increasing the protein in your diet.

How much protein, and in turn calories, can you add without increasing your body fat? In one study, young, healthy men consumed 4.4 grams (g) of protein per kilogram (kg) of body weight per day for eight weeks. This is nearly four times the recommended amount. 

This amount of protein provides an additional 1,200 calories for the average 150-pound, or 68-kilogram, person. With simple calorie counting, you’d expect these men to have gained a lot of weight. However, even with this increase in calories, the men in this study did not gain any body fat or muscle mass.

Even more reasonable increases in protein lead to benefits, as one study demonstrates. The study involved 39 physically active men and women who were about 21-years-old and with a normal body mass index of BMI of 22–29.

First, the researchers put the participants on a low-calorie diet that was about a 40% reduction from what they normally ate. Then, they supplemented the participants with three different levels of protein. 

One group got the recommended dietary allowance, or RDA, for protein, which was 0.8 g per kg of body weight, the second group got two times the RDA at 1.6 g per kg, and the third group got three times the RDA at 2.4 g of protein per kg of body weight.

Both the second and third groups, at double and triple the RDA, preserved muscle mass and reduced body fat to the greatest extent while on a low calorie diet. The group that supplemented with two times the RDA of protein had the greatest effects. 

This means that during calorie restriction, a shift to increase the number of calories you get from protein, which would replace many of the calories you get from carbohydrates and fats, will improve body composition. Even supplementing with milk has been shown to improve body composition when trying to lose weight.

Protein and Dairy Benefits

Researchers put overweight and obese women on an exercise and low calorie diet for 16 weeks with varying amounts of protein and dairy. They found that all of the women lost a significant amount of weight, but the high-protein and high-dairy group—which was about 30% protein and 15% dairy—lost the most fat from their stomach area and from their visceral fat, which is the fat surrounding your organs and is linked to many health problems. 

Additionally, only the high-protein, high-dairy group was able to add muscle mass. Finally, protein intake from milk and other sources may help decrease your waist circumference and maximize your strength. 

Therefore, when it comes to achieving your ideal body composition, putting yourself on a low-calorie diet probably will not help you to meet your goal in the long run. While a deficit in calories does create weight loss, the type and quality of your calories matters, too. 

According to Professor Ormsbee, if you want to lose fat, but want to preserve muscle, or even add muscle to help with your performance, mobility, and metabolism, then you should seriously consider increasing the amount of protein you eat.

This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Dr. Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.

About Kate Findley 401 Articles
Kate is a writer, novelist, and blogger living in Los Angeles. She has been writing for The Great Courses since 2017. It incorporates her two favorite things: writing and learning.