The Protein Power-Up
The Role of Protein in Enhancing Body Composition, Strength, Performance, and Longevity
So you’ve been putting in the work, earning XP, and leveling up. What else can you do? There must be some sort of power-up, some kind of potion or enchantment that will aid your adventure… and there is! Protein. You’ll hear every gym-bro-scientist in the realm championing their favorite macronutrient. And they’re absolutely right. When it comes to optimizing our physical performance and achieving our fitness goals, nutrition and recovery play a vital role (almost as important than as stimulus itself). We’ll delve into the scientific findings from recent studies to highlight the significance of protein in improving body composition, reducing the length of morbidity, increasing strength, and enhancing overall performance.
Body Composition: Creating a Healthy and Heroic Physique
From Korra to Kratos, there are some EPIC physiques on the map. One thing in common? It’s not body weight… It’s body composition. A high-protein diet has been shown to have a positive impact on body composition, which refers to the proportion of fat, muscle, and bone in the body. Body composition has been shown to have a significant impact on morbidity, or the incidence of disease and illness. Several studies have investigated the relationship between body composition and morbidity, and have found that changes in body composition can have a negative impact on health outcomes.
One study found that changes in body composition, specifically an increase in fat deposits below the level of injury, can be a "devastating co-morbidity" for individuals with spinal cord injuries [1]. Another study found that low muscle mass was independently associated with increased morbidity and mortality in individuals with chronic obstructive pulmonary disease (COPD) [2].
Protein has a higher thermic effect of food (TEF) compared to carbohydrates and fats, meaning that it requires more energy to digest, absorb, and process. This results in an increase in calorie expenditure, contributing to weight management and potentially reducing body fat levels. In another study, aspiring female physique athletes who followed a high-protein diet experienced a significant increase in fat-free mass and a decrease in fat mass compared to those on a lower protein diet. These findings highlight the ability of protein to support the development of a leaner, more muscular physique [3].
Strength and Hypertrophy: The Muscular Power-Up
Protein intake plays a vital role in building strength and promoting muscular hypertrophy (“hyper-,” to increase and “-trophy,” for nourishment, meaning to make a muscle larger). The amino acids derived from dietary protein are the building blocks for muscle tissue repair and growth. One study showed that higher habitual protein intake was associated with greater increases in skeletal muscle mass, lower limb lean soft tissue, upper limb lean soft tissue, and overall muscular strength [4].
The study conducted by Morton et al. (2018) is the largest meta-analysis to date on interventions including dietary protein supplementation with muscle and strength-related outcomes during prolonged resistance exercise training (RET). The study found that dietary protein supplementation augmented RET-induced increases in one-repetition maximum (1RM) strength and fat-free mass (FFM). The data showed that dietary protein supplementation is both sufficient and necessary to optimize RET adaptations in muscle mass and strength. The study also found that protein supplementation was more effective in resistance-trained individuals, and did not increase beyond total protein intakes of ~1.6 g/kg/day. The study concluded that RET is a far more potent stimulus for increasing muscle strength than the addition of dietary protein supplementation. However, protein supplementation may slightly augment changes in 1RM, which may be important for those competing in powerlifting or weightlifting. The study suggests that if an increase in 1RM is the objective of an RET program, a sufficient amount of work and practice at or around the 1RM is far more influential than protein supplementation. Overall, the study provides evidence that protein supplementation can enhance RET-induced gains in muscle mass and strength, particularly in resistance-trained individuals [5].
Age-Related Muscle Decline: Defying Sarcopenia
As we continue to level up (in age and in life), maintaining muscle mass becomes increasingly challenging. However, a high-protein diet combined with exercise can help counteract age-related muscle decline, known as sarcopenia. Current guidelines for protein intake and physical activity do not reflect recent knowledge on sarcopenia prevention [6]. Higher protein intakes of 1.2-1.5 g/kg body mass have been suggested for older adults [7]. Protein supplementation has also been shown to preserve lean body mass and prevent frailty, which are accepted intervention targets for reducing the risk of sarcopenia [8].
In a study published in the Journal of the American Geriatrics Society, researchers investigated the effects of resistance training and increased protein intake on muscle mass and strength in elderly women. The study involved 30 women aged 65-91 years who were randomly assigned to either a resistance training group or a control group. The resistance training group performed exercises using weights and resistance bands three times per week for 12 weeks, while the control group did not engage in any exercise program. Both groups were instructed to maintain their usual diet, but the resistance training group was also given a protein supplement to consume after each exercise session. The results of the study showed that the resistance training group had significant improvements in muscle mass, strength, and physical function compared to the control group. Specifically, the resistance training group had a 2.3% increase in lean body mass, a 10.9% increase in leg press strength, and a 12.6% increase in walking speed. These improvements were significantly greater than those observed in the control group .
Appetite Regulation: Stealth Snacking and Seeking Satiety
We all have different relationships with food. Sometimes, hunger and satiety (fullness) cues can be confusing. Keeping protein in your inventory has been shown to have a significant impact on satiety and hunger, which can in turn affect weight loss strategies. Several studies have investigated the relationship between protein intake and satiety, and have found that protein intake can enhance satiety and promote weight loss.
One study published in the journal Cell Metabolism investigated the role of peptide YY (PYY) in protein-mediated satiation and body weight regulation [9]. The study involved 12 healthy volunteers who were given three different meals with varying protein content. The results showed that the meal with the highest protein content produced the greatest increase in PYY levels, which was associated with increased satiety and decreased hunger [9].
Another study published in the Journal of the American College of Nutrition reviewed the effects of high protein diets on thermogenesis, satiety, and weight loss [10]. The review found convincing evidence that a higher protein intake increases thermogenesis and satiety compared to diets of lower protein content. This means that a higher protein intake can increase the number of calories burned and reduce hunger, which can lead to weight loss [10].
References:
[1] Md, Pa (2019). Activity-based interventions and the continuum of spinal cord injury research. The Journal of Spinal Cord Medicine, 1(42), 1-1. https://doi.org/10.1080/10790268.2018.1543518
[2] Rutten, Bakke, Pillai, Wagers, Grydeland, Gulsvik, … & Wouters (2012). The association between body composition and self-reported co-morbidity in subjects with chronic obstructive pulmonary disease. OJIM, 02(02), 100-106. https://doi.org/10.4236/ojim.2012.22019
[3] Olenick AA, Pearson RC, Jenkins NT. Training Status Impacts Metabolic Response to A High-Protein Weight Loss Diet in Recreationally Resistance-Trained Females. Int J Exerc Sci. 2023 Mar 1;16(2):377-392.
[4] Nabuco HC, Tomeleri CM, Junior PS, et al. Effects of higher habitual protein intake on resistance-training-induced changes in body composition and muscular strength in untrained older women: A clinical trial study. Nutr Health. 2019 Sep;25(3):165-173.
[5] Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018 Mar;52(6):376-384. doi: 10.1136/bjsports-2017-097608. Epub 2017 Jul 11. Erratum in: Br J Sports Med. 2020 Oct;54(19):e7. PMID: 28698222; PMCID: PMC5867436.
[6] Oliveira, Dionne, Prado (2018). Are Canadian protein and physical activity guidelines optimal for sarcopenia prevention in older adults?. Appl. Physiol. Nutr. Metab., 12(43), 1215-1223. https://doi.org/10.1139/apnm-2018-0141
[7] Beaudry, Devries (2019). Nutritional Strategies to Combat Type 2 Diabetes in Aging Adults: The Importance of Protein. Front. Nutr., (6). https://doi.org/10.3389/fnut.2019.00138
[8] Tuttiett, Corfe, Stevenson, Hill, Williams (2020). Does timing of a protein supplement affect energy and macronutrient intakes and measures of appetite in a middle-older aged adult population?. Proc. Nutr. Soc., OCE3(79). https://doi.org/10.1017/s0029665120007788
[9] Batterham, Heffron, Kapoor, Chivers, Chandarana, Herzog, … & Withers (2006). Critical role for peptide YY in protein-mediated satiation and body-weight regulation. Cell Metabolism, 3(4), 223-233. https://doi.org/10.1016/j.cmet.2006.08.001
[10] Halton, Hu (2004). The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review. Journal of the American College of Nutrition, 5(23), 373-385. https://doi.org/10.1080/07315724.2004.10719381
