Studies have shown that when either protein or carbohydrate supplements (i.e., 25 grams) are administered to resistance-trained individuals, protein but not carbohydrate increases lean muscle mass. Other literature reviews have found that protein supplementation augments lean muscle mass when combined with resistance exercise. Low protein intake drives food intake resulting in overeating.



  • The optimal protein intake to lose body fat loss diet consists of around 1.5 grams per pound of bodyweight
  • When not dieting, greater protein doses greater than 1 gram per pound of body weight don’t increase muscle growth.
  • Overfeeding studies with protein have not found additional gains in body fat.
  • High protein diets result in greater appetite suppression.


Protein is essential to building muscle and provides structural integrity and functionality for bones, tissues, and organs. It can produce hormones, enzymes, hemoglobin, and plasma proteins such as albumin. While dieting, controlling hunger is key to successful dieting.

A high protein diet can decrease appetite, increase energy expenditure, and maintain lean mass, positively affecting body composition. A lean muscle diet of high-protein foods rich in essential amino acids can contribute to weight loss.


Some researchers have suggested that decreases in protein could partly be a piece of the obesity puzzle. A review of hunter-gather diets suggested that ancient man’s typical diet would be 19-35% protein, 22-40% carbohydrate, and 28-58% for fat.(1) The latest dietary trend from 1999 to 2016 showed that Americans’ had a small increase in protein intake from 15.5% to 16.4%. This reduction in foods high in protein may be a contributing factor to obesity.

The increases came from both animal and plant-based sources. Energy intake from total carbohydrates declined from 52.5% to 50.5%, and total fat increased from 32% to 33.2%.(2) How can we keep saying that carbohydrates make society fat when carbohydrate intake is decreasing and obesity levels are still rising?

Dietary proteins contain amino acids, the building blocks of protein needed for health and normal functioning. There are approximately 20 amino acids required by the body, with nine amino acids being essential and the other 11 non-essential, which the body can make.

Unlike carbohydrates or fat, protein has no storage in the human body; thus, a constant supply of amino acids must be consumed throughout the diet. Increasing muscle mass is important for strength and performance, but it is also important for health. Sarcopenia, or muscle loss, is a serious disease that affects millions of elderly adults.


Decreased muscle mass also increases the risks of such diseases as type 2 diabetes and obesity.(3) One of the biggest fitness myths you hear is that building new muscle helps you burn more calories all day. Muscle burns calories at a rate of 54 kj/kg per day (i.e., 6 calories per 1.2 pounds of muscle).(4) So much for the myth that you can eat whatever you want because you have more muscle!

Most people are only concerned with how to build lean muscle for aesthetics. They think of its use for lifting heavy weights and enhancing athletic performance, but muscle has more functions than just flexing biceps.

Muscle has a diverse range of metabolic functions, such as 1.) muscle is an endocrine organ that produces special myokines in muscles released during exercise. 2.) Muscle is a key site of glucose uptake and storage and is critical for maintaining blood glucose control. 3.) Muscle contains 95% of the body’s creatine.(5)

The RDA is geared toward sedentary people who are not active.


As mentioned previously, the obesity epidemic is increasing. What would happen if all Americans switched to a high-protein diet?

The RDA protein intake is approximately .8 g/kg of bodyweight or .4 grams per pound of bodyweight. Does this meager amount of protein contribute to a healthy, strong body?

The RDA is geared toward sedentary people who are not active. It is concerned about preventing protein deficiency and not optimal health and performance. The RDA is certainly not designed for people who want to gain muscle and lose body fat. As all bodybuilders know, following a low-protein diet is not how to get lean muscle increases.

In a meta-analysis of the relationship between escalating dosages of protein and lean muscle mass, it was found that even slightly increasing protein intake for several months in a dose-dependent manner over a range of dosages (.5-3.5 g/kg/bw or .2-1.6 grams per pound of bw) can increase lean muscle mass.(6)

A high-protein breakfast and high-protein snacks throughout the day are a great way to optimize protein synthesis. A whey protein shake is a good source of protein to boost daily protein intake for those not getting enough.


For many years, scientists and scholars have questioned the validity of the RDA’s stance on protein. In an article titled “Protein ‘requirements’ beyond the RDA: implications for optimizing health,” one of the leading experts in protein metabolism, Dr. Stuart Philips, wrote.(7) In the article, Dr. Philips discusses the following beneficial effects of protein for the general population:

a.) High-protein diets are beneficial for preventing muscle loss and sarcopenia (i.e., loss of muscle) in the elderly.

b.) Higher protein benefits weight management, losing body fat, and preserving lean muscle mass.

c.) Higher protein has beneficial effects on reducing appetite, leading to reduced calories.

d.) Protein (~30 grams per meal) should be evenly distributed throughout the day for optimal benefits.

e.) Healthy adults should consume between ~1.2-1.6 g/kg of body weight per day (.5-.7 grams per pound of body weight).

f.) High-quality meals from animal-based sources (i.e., milk, meat, eggs, poultry) provide a rich source of essential amino acids to stimulate maximal protein synthesis.

Protein Supplementation Studies

In a meta-analysis, 22 randomized studies compared protein supplementation with placebo controls in 680 subjects. Their analysis showed that protein supplementation significantly augmented both the increase in muscle mass (0.81 kg (1.78 pounds) more in young and 0.48 kg (1.05 pounds) more in old) and strength (1-repetition maximum [RM] increased by 14.4 kg (31.6 pounds) more in the young and 13.1 kg (28.8 pounds) in old) that occurred with training, and these improvements in adaptation were independent of training status.(8)

Thus, if you are not consuming adequate protein in your diet, it can affect performance and lean mass. Researchers examined the impact of switching from a typical American diet to a high-protein diet. Participants were randomized to either a Western diet consisting (55% carbohydrates, 15% protein, and 30% fat) or a high protein diet (35% carbohydrates, 40% protein, 25% fat). The total calories were the same in both groups.

The subjects had to stay inside a metabolic chamber for 32 hours, which measured their metabolic rate during the study. The subjects on the high protein diet increased energy expenditure (i.e., 82 calories per day), increased fat oxidation, and reduced fat intake. Compared to the western diet, the high protein diet led to a decrease in energy intake of ~112 calories per day. A high-protein diet has a greater thermic effect of food, contributing to long-term fat loss.

The researchers suggested that high-protein intake to lose fat compared to a traditional western diet.(9) A study shows increased dietary protein has a more beneficial effect on weight loss than increasing carbohydrates for obese and overweight individuals. Furthermore, it was found that protein had a more beneficial effect on body weight than dietary fiber.(10)

Defining High Protein Diets

There are mixed studies regarding protein intake and possibly because of the definition of what researchers classify as “high-protein.” Protein should always be based on grams per kg of body weight, or an even better standard is grams per kg of fat-free mass or lean mass. It has been found that basing protein on fat-free mass is a more reliable indicator of protein intake than g/kg/bw.

A study found that basing protein of g/kg/bw tended to overestimate protein in most cases.(11) For example, a person can be in a large caloric surplus and gain excess body fat, resulting in large increases in body weight. Yet, muscle mass has not changed but based on the formula (grams per kilogram or g/kg/bw), protein intake would increase.

The other issue is that it is not gender-specific, and females have less lean muscle mass than males. Keep in mind that the studies mentioned by Antonio and others have found that a protein surplus will not result in excess body fat. For those basing protein intake on lean mass or fat-free mass (FFM), a reasonable range for protein is 1.8-2.6 g/kg (.8-.5 grams per pound of body weight) of lean mass.


1.         Cordain L, Miller JB, Eaton SB, Mann N, Holt SH, Speth JD. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. The American Journal of Clinical Nutrition. 2000;71(3):682-92.

2.         Shan Z, Rehm CD, Rogers G, Ruan M, Wang DD, Hu FB, et al. Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016. JAMA. 2019;322(12):1178.

3.         Wolfe RR. The underappreciated role of muscle in health and disease. Am J Clin Nutr. 2006;84(3):475-82.

4.         Illner K, Brinkmann G, Heller M, Bosy-Westphal A, Müller MJ. Metabolically active components of fat-free mass and resting energy expenditure in nonobese adults. Am J Physiol Endocrinol Metab. 2000;278(2):E308-15.

5.         Duda K, Majerczak J, Nieckarz Z, Heymsfield SB, Zoladz JA. Chapter 1 – Human Body Composition and Muscle Mass. In: Zoladz JA, editor. Muscle and Exercise Physiology: Academic Press; 2019. p. 3-26.

6.         Tagawa R, Watanabe D, Ito K, Ueda K, Nakayama K, Sanbongi C, et al. Dose–response relationship between protein intake and muscle mass increase: a systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews. 2021;79(1):66-75.

7.         Phillips SM, Chevalier S, Leidy HJ. Protein “requirements” beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition, and Metabolism. 2016;41(5):565-72.


8.         Cermak NM, Res PT, de Groot LC, Saris WH, van Loon LJ. Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. Am J Clin Nutr. 2012;96(6):1454-64.

9.         Oliveira CLP, Boulé NG, Sharma AM, Elliott SA, Siervo M, Ghosh S, et al. A high-protein total diet replacement increases energy expenditure and leads to negative fat balance in healthy, normal-weight adults. The American Journal of Clinical Nutrition. 2021;113(2):476-87.

10.       Hansen TT, Astrup A, Sjödin A. Are Dietary Proteins the Key to Successful Body Weight Management? A Systematic Review and Meta-Analysis of Studies Assessing Body Weight Outcomes after Interventions with Increased Dietary Protein. Nutrients. 2021;13(9):3193.

11.       Dekker IM, van Rijssen NM, Verreijen A, Weijs PJ, de Boer WBE, Terpstra D, et al. Calculation of protein requirements; a comparison of calculations based on bodyweight and fat free mass. Clin Nutr ESPEN. 2022;48:378-85.

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