Current Opinion
Extra Calories Increase Fat Mass While Protein Increases Lean Mass
By David Heber, M.D., Ph.D.
Dr. George Bray, a member of the Herbalife Nutrition Institute editorial board and colleagues at the Pennington Biomedical Research Center at Louisiana State University (1) in a randomized controlled trial evaluated the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition in a controlled setting where they overfed 1000 Calories per day and carefully measured the extra food calories eaten. They found that body fat increased in proportion to excess calories but overall weight gain was less with low protein relative to normal or high protein diets. These findings have important ramifications because the Western diet tends to be high in fat and carbohydrates and low in protein. The study results also suggest that body weight may underestimate the true hazards of over nutrition, since excess weight can be either lean or fat tissue.
This study consisted of 25 healthy weight-stable male and female volunteers, 18-35 years old with a BMI of 19-30. The subjects were confined to an in-house environment in which they were deliberately overfed approximately 1000 calories daily (40% more energy than required for weight maintenance) with diets of varying protein content for 8 weeks. Overeating produced significantly less weight gain in the low protein group (approximately 3 kg) compared with the normal or high protein groups (approximately 6 kg). Total body fat measured by dual-energy x-ray absorptiometry increased similarly in all 3 groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure and body protein increased significantly only with the normal and high protein diets but not with the low protein diet.
This study demonstrates how low protein foods with hidden sugars or fats may be contributing to the obesity epidemic. Sugars such as sucrose, fructose, and high fructose corn syrup are converted efficiently to fat with calorie excess 12 (2) Carbohydrates and protein elicit different signaling pathways for muscle and fat cells.(3)13 Therefore, when individuals consume excess carbohydrates out of proportion to protein, the body may gain less weight than when protein is consumed in adequate amounts. The study by Bray et al (1) demonstrated that the lesser added weight consists largely of fat mass rather than lean body mass when excess calories were the same. Moreover, added fat calories (including hidden fat in processed foods) consumed in excess will also lead to weight gain contributing to the obesity epidemic (4).
A large and well-accepted body of scientific evidence indicates that protein is the most satiating of the macronutrients. High protein diets providing 25% of total energy compared with diets comparable with the low protein diet in the study by Bray et al (1) lead to greater weight loss in free-living individuals(5). In addition, high protein diets inhibit weight regain after weight loss in free-living populations(6). Therefore, reduced total caloric intake with increased intakes of low-fat, protein-rich foods may contribute to more successful weight loss in the long-term due to the effects on resting energy expenditure observed in this study.
It is possible through exercise and adequate protein to build lean body mass more efficiently than with a low protein diet.(7). Because muscle weighs more than fat per unit of volume, it is possible to gain weight as muscle mass while reducing body fat, waist circumference and intra-abdominal fat. Weight loss with adequate protein can maintain lean muscle mass while reducing body fat.
1. Bray GA, Smith SR, de Jonge L, et al. Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA. 2012;307(1):47–55.
2. Stanhope KL, Schwarz JM, Keim NL, et al. Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009;119(5):1322–1334.
3. Devkota S, Layman DK Increased ratio of dietary carbohydrate to protein shifts the focus of metabolic signaling from skeletal muscle to adipose. Nutr Metab (Lond). 2011;8:13.
4. Heber D. An integrative view of obesity. Am J Clin Nutr. 2010;91(1):280S–283S
5. Skov AR, Toubro S, Rønn B, Holm L, Astrup A andomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obes Relat Metab Disord. 1999;23(5):528–536
6. Westerterp-Plantenga MS, Nieuwenhuizen A,Tomé D,Soenen S,Westerterp KR. Dietary protein, weight loss, and weight maintenance. Annu Rev Nutr. 2009;29:21–41
7. Phillips SM Physiologic and molecular bases of muscle hypertrophy and atrophy: impact of resistance exercise on human skeletal muscle (protein and exercise dose effects). Appl Physiol Nutr Metab. 2009;34(3):403–410.
8. World Health Organization Obesity and overweight fact sheet No. 311: updated March 2011. http://www.who.int/mediacentre/factsheets/fs311/en/. Accessed December 12, 2011.
9. Misra A, Singhal N, Sivakumar B, Bhagat N, Jaiswal A, Khurana L Nutrition transition in India: secular trends in dietary intake and their relationship to diet-related non-communicable diseases. J Diabetes. 2011;3(4):278–292. Shen J, Goyal A, Sperling L The emerging epidemic of obesity, diabetes, and the metabolic syndrome in china. Cardiol Res Pract. 2012;2012:178675
1. Bray GA, Smith SR, de Jonge L, et al. Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA. 2012;307(1):47–55.
2. Stanhope KL, Schwarz JM, Keim NL, et al. Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009;119(5):1322–1334.
3. Devkota S, Layman DK Increased ratio of dietary carbohydrate to protein shifts the focus of metabolic signaling from skeletal muscle to adipose. Nutr Metab (Lond). 2011;8:13.
4. Heber D. An integrative view of obesity. Am J Clin Nutr. 2010;91(1):280S–283S
5. Skov AR, Toubro S, Rønn B, Holm L, Astrup A andomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obes Relat Metab Disord. 1999;23(5):528–536
6. Westerterp-Plantenga MS, Nieuwenhuizen A,Tomé D,Soenen S,Westerterp KR. Dietary protein, weight loss, and weight maintenance. Annu Rev Nutr. 2009;29:21–41
7. Phillips SM Physiologic and molecular bases of muscle hypertrophy and atrophy: impact of resistance exercise on human skeletal muscle (protein and exercise dose effects). Appl Physiol Nutr Metab. 2009;34(3):403–410.
8. World Health Organization Obesity and overweight fact sheet No. 311: updated March 2011. http://www.who.int/mediacentre/factsheets/fs311/en/. Accessed December 12, 2011.
9. Misra A, Singhal N, Sivakumar B, Bhagat N, Jaiswal A, Khurana L Nutrition transition in India: secular trends in dietary intake and their relationship to diet-related non-communicable diseases. J Diabetes. 2011;3(4):278–292. Shen J, Goyal A, Sperling L The emerging epidemic of obesity, diabetes, and the metabolic syndrome in china. Cardiol Res Pract. 2012;2012:178675
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