Feasting on Protein Does Not Increase Body Fat

A calorie is a calorie, right ? For years nutritionists have sworn that all calories are the same. Yet, over the course of time a number of studies have proven this age long “truth” is nothing more than a myth.


One of the most recent studies focused on the impact of high protein diet on weight gain in resistance training individuals. The results of the study were obtained over a course of 8 weeks by monitoring the weight gain in two groups of resistance training individuals – one on a high protein diet, the other one consuming normal amounts of protein.

While both groups continued with the same training regime, the first group increased their protein intake to 4.4 grams per kg of bodyweight. Both groups were instructed to continue consuming the same diet as before in all other respect. In other words, the intake of fats and carbohydrates remained the same as before. All indicators of body composition (weight, body fat and lean muscle mass percentage), as well as the volume of training and food intake, were determined at the beginning of the research period, and over the next 8 weeks.

The results reveal that the protein and calories intake in the high protein group were significantly greater before a workout than after a workout. In addition, this group recorded a significantly greater amount of consumed protein and calories than the group that consumed normal protein quantities.

For illustration, the average consumption of protein in the high protein group was 307 ± 69 grams, while the average consumption in the normal group was 138 ± 42. Or, the average daily consumption of protein was 4.4 ± 0.8 g. per each kg. of bodyweight in the former, and 1.8 ± 0.4 g. per each kg. of bodyweight in the latter. The training volume of both groups remained the same. At the end of the trial period, the researchers did not recorded any significant alterations of in respect of body weight or body fat percentage.

The results of the study are very important because they show for the first time that overfeeding with protein does not increase the body fat composition in people who are working out. The results are contrasted to some of other studies which recorded an increase in body weight, fat mass and lean body mass. Yet, it should be noted that the previous studies were involved individuals that were not exercising.

One of the most intriguing aspects of research is that the high-protein group did not gain weight despite consuming a significantly more calories – 800 per day to be exact. However, these calories were obtained from the extra protein in their diet. According to the researchers involved in this study, one of the primary reasons why the increased amount of calories did not result in increased weight is the thermal effect of protein, which increases resting energy expenditure. This thermal effect may be the reason why we don’t gain bodyweight when overfeeding with protein.

According to the research the resting energy expenditure can increase from 17 to 21 percent after consuming a 60 gram meal high in protein. That is why high protein snacks are a perfect option to satisfy your cravings and still keep the weight off.   Well, that was the good news. The bad news is for all of you hoping that overfeeding with protein will make you grow your muscles faster. While the body fat percentage remained in check in the high protein group, so did the lean muscle mass.


Bray GA, Smith SR, de Jonge L, Xie H, Rood J, Martin CK, Most M, Brock C, Mancuso S, Redman LM: Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA 2012, 307:47-55.

Belko AZ, Barbieri TF, Wong EC: Effect of energy and protein intake and exercise intensity on the thermic effect of food. Am J Clin Nutr 1986, 43:863-869.

Maljaars PW, Peters HP, Mela DJ, Masclee AA: Ileal brake: a sensible food target for appetite control. A review. Physiol Behav 2008, 95:271-281.

Lemon PW: Protein and amino acid needs of the strength athlete. Int J Sport Nutr 1991, 1:127-145.

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