High quality protein is absolutely essential for building lean tissue and promoting recovery from arduous training. But traditionally, higher protein diets have been viewed with a negative connotation and were proposed to cause kidney issues.
Although this viewpoint is totally not supported in the sports medicine field, it is even losing its momentum in the medical community as more and more evidence on the benefits of higher protein intake is being discovered.
Protein is indispensable to human health and is the primary source of amino acids, the structural components of all body proteins. Inadequate dietary protein intake may result in loss of skeletal muscle mass, as endogenous proteins are rapidly degraded to provide amino acid precursors to sustain protein turnover and energy metabolism.
To prevent muscle loss, the Institute of Medicine and World Health Organization established recommended dietary allowances (RDA) of 0.8 g/kg/day and 0.83 g/kg/day, respectively.
However, an increase in dietary protein intake can be metabolically advantageous, mainly for overweight and obese adults attempting weight loss, and also for physically active people such as athletes and military personnel, during periods of increased caloric expenditure and metabolic demand (1).
Let’s take a look at some important highlights from the last 10 years of research on the metabolic advantages conferred by consuming higher protein:
Higher protein, healthy weight management & metabolic advantages of dairy protein
The effects of higher protein diets on body composition have been extensively researched. The following are some key points on the effects of higher protein diets in managing bodyweight and benefits of dairy rich protein intake.
Higher protein and glycemic regulation
Below are some key evidence-based highlights on higher protein and glycemic regulation:
Higher protein on calcium retention and bone health
Protein is a major structural component of bone; therefore, maintaining adequate dietary protein and calcium intake is crucial in order to conserve optimum bone health. Here are some key points on higher protein, calcium retention and bone health.
Latest evidence on higher protein and metabolic regulation?
Study 1: To date, no inpatient metabolic balance studies have evaluated the exact role of a controlled diet with increased protein on energy expenditure, macronutrient oxidation rates and balances, and metabolic blood markers. In addition, there are no studies with this type of intervention that also utilized state of the art methodology in a controlled environment in healthy males and females with normal body weight.
A very recent well-designed research study utilized inpatient metabolic balance study to compare the impact of an isocaloric (i.e., same number of calories) high protein vs control diet on energy expenditure, macronutrient oxidation rates and balances, and metabolic blood markers in healthy female and male adults (8).
There were two isocaloric groups with the following diet composition:
1) High protein - 35% carbohydrate, 40% protein, and 25% fat
2) Control - 55% carbohydrate, 15% protein, and 30% fat).
Participants received the prescribed diets for 32 hours while inside a whole-body calorimetry unit.
Key highlights of this study:
Conclusion: A high protein diet resulted in greater fat loss compared to an isocaloric diet with lower amounts of protein. With all other things being equal, more protein is beneficial for lean body mass retention and generating greater fat loss. Metabolic advantage to reduced carb is not due to the lower carbs, it’s due to the higher protein intake (8).
Study 2: Although higher protein diets are gaining popularity worldwide, little is known about the effects on the mechanisms involved in body weight regulation of females and males, especially when associated with exercise. It is important to study the physiological impact of these strategies in a healthy, normal-weight population without the confounding effects of obesity and other comorbidities.
A very recent study investigated the effects of consuming a high-protein meal replacement versus a control breakfast preceding an acute bout of moderate-intensity exercise on selected components of exercise energy metabolism, appetite sensations, and metabolic blood markers in healthy, normal-weight young adults of both sexes (9).
The two isocaloric arms in this study had the following meal composition:
1) High protein - 30% carbohydrate, 43% protein, and 27% fat
2) Control - 55% carbohydrate, 15% protein, and 30% fat
Following breakfast, participants performed a moderate-intensity aerobic exercise while inside a whole-body calorimetry unit. Energy expenditure, macronutrient oxidation, appetite sensations, and metabolic blood markers were assessed.
Key highlights of this study:
Conclusion: This study showed that, compared to a standard North American breakfast, an isocaloric high protein meal replacement led to higher fat oxidation during exercise, suppression of hunger, and improved metabolic profile after exercise.
These results highlight the benefits of a high protein meal replacement during and after an exercise session on energy metabolism, appetite sensations, and metabolic blood markers of healthy, normal-weight adults of both sexes, and provides further insight into the potential role of these combined strategies for weight management (9).
Summary and practical applications
Increasing dietary protein is safe and can elicit several favorable metabolic adaptations including improved weight management (i.e., fat loss, lean body mass retention, and body weight sustainment), glycemic regulation, calcium retention, and long-term bone health.
Recent emerging evidence also suggests that consuming dairy may potentiate the metabolic advantages of higher protein diets, primarily due to the digestive, absorptive properties and essential amino acid content of dairy proteins.
As far as the recommended amount of protein. The two studies above utilized about 2.5 g/kg/bodyweight of protein. Anywhere from 1.6 to 2.4 g/kg/bodyweight or 2.3 to 3.1 g/kg of lean body mass will get you the most benefits from protein.
It’s clear that higher protein enhances fat oxidation at rest and during exercise, increases thermic effect of feeding and total energy expenditure, suppresses hunger and improves our overall metabolic profile.
1.Phillips, S. M. (2014) A brief review of higher dietary protein diets in weight loss: a focus on athletes. Sports Med 44 Suppl 2, S149-153
2.Tang, M., Armstrong, C. L., Leidy, H. J., and Campbell, W. W. (2013) Normal vs. high-protein weight loss diets in men: effects on body composition and indices of metabolic syndrome. Obesity (Silver Spring) 21, E204-210
3.Josse, A. R., Atkinson, S. A., Tarnopolsky, M. A., and Phillips, S. M. (2011) Increased consumption of dairy foods and protein during diet- and exercise-induced weight loss promotes fat mass loss and lean mass gain in overweight and obese premenopausal women. J Nutr 141, 1626-1634
4.Larsen, T. M., Dalskov, S. M., van Baak, M., Jebb, S. A., Papadaki, A., Pfeiffer, A. F., Martinez, J. A., Handjieva-Darlenska, T., Kunesova, M., Pihlsgard, M., Stender, S., Holst, C., Saris, W. H., Astrup, A., Diet, O., and Genes, P. (2010) Diets with high or low protein content and glycemic index for weight-loss maintenance. N Engl J Med 363, 2102-2113
5.Zemel, M. B. (2003) Mechanisms of dairy modulation of adiposity. J Nutr 133, 252S-256S
6.Leidy, H. J. (2014) Increased dietary protein as a dietary strategy to prevent and/or treat obesity. Mo Med 111, 54-58
7.Fumeron, F., Lamri, A., Abi Khalil, C., Jaziri, R., Porchay-Balderelli, I., Lantieri, O., Vol, S., Balkau, B., Marre, M., and Data from the Epidemiological Study on the Insulin Resistance Syndrome Study, G. (2011) Dairy consumption and the incidence of hyperglycemia and the metabolic syndrome: results from a french prospective study, Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR). Diabetes Care 34, 813-817
8.Oliveira, C. L. P., Boule, N. G., Sharma, A. M., Elliott, S. A., Siervo, M., Ghosh, S., Berg, A., and Prado, C. M. (2021) A high-protein total diet replacement increases energy expenditure and leads to negative fat balance in healthy, normal-weight adults. Am J Clin Nutr 113, 476-487
9.Oliveira, C. L. P., Boule, N. G., Berg, A., Sharma, A. M., Elliott, S. A., Siervo, M., Ghosh, S., and Prado, C. M. (2021) Consumption of a High-Protein Meal Replacement Leads to Higher Fat Oxidation, Suppression of Hunger, and Improved Metabolic Profile After an Exercise Session. Nutrients 13