Introduction to Protein
In the last few years, the popularity of high protein diets, protein supplements, and the overall interest in increasing protein in the diet has boomed. The protein supplement market was valued at $20.47 billion in 2021 and is expected to grow at an annual rate of 8.5% between 2021 and 2030 (Protein Supplement Market Size Report). The RDA for protein is 0.8g/kg of body weight, meaning for the average healthy adult sedentary male about 56 grams, and the average healthy adult sedentary female 46 grams. Most American adults eat about 100g of protein a day, well over the recommended amount (Rabin). Browsing the snack aisle at the food store, you’re guaranteed to see many products advertised as being packed with protein, including ice cream, cookies, pasta, waffles, bread, and pancakes. While protein is necessary for the diet, some argue that we have taken our protein obsession too far and that there are negative effects of protein overconsumption.
Protein’s Role In Weight Loss and Muscle Building
Protein is a key macronutrient with many important jobs in the body. It is made up of building blocks called amino acids that our body uses to make important hormones and enzymes, build and repair muscle and can be used as an energy source when other macronutrient levels are low. The gain in popularity of increased protein intake can be attributed to multiple factors. A big reason is the negative perception of carbohydrates on weight and health, leading people to turn to protein instead. While all macronutrients should be consumed to sustain optimal health, there is evidence to show protein’s positive effects on weight loss. Higher protein diets (1.2 to 1.6g/kg body weight) have been shown to provide improvements in appetite, satiety, and weight management (Leidy). Compared to fats and carbohydrates, protein has the highest thermic effect of food, meaning it utilizes the most energy to digest and absorb, a reason it is thought to aid in weight loss (Leidy). A study done on 1,063 overweight individuals compared a low protein and a high protein diet for weight loss. The two groups were in a similar calorie deficit, but the high protein group had more weight and fat loss while preserving more lean body mass than the low protein group (Leidy). The protein craze is not only attributed to its role in weight loss, but also its role in building muscle. In a systematic review, looking at protein supplementation’s effect on muscle mass and strength in healthy adults, it found that protein supplementation does promote greater muscle gains in lean mass as the duration and frequency of resistance training increases, but in the initial weeks of beginning resistance training, protein supplementation had no effect on muscle building (Pasiakos). With protein’s positive effects on weight loss and muscle gain, it is obvious why the public believes that the more the better when it comes to protein. But, more and more protein does not necessarily mean more muscle gain and more weight loss.
How to Eat Protein To Maximize Muscle Building
It may seem logical that to reap the benefits of protein, eating as much as possible in a day would be the best method. Studies have found that eating 300 grams of protein a day, does not have any greater benefits than someone who eats only 110 grams a day (Rabin). Many studies propose that muscle protein synthesis (building of lean muscle tissue) is maximized in adults with 20-25 g of high-quality protein per meal. High-quality proteins refer to complete proteins or those that contain all essential amino acids. These include food items such as fish, meat, chicken, eggs, soy, and quinoa. For vegetarians and vegans, quality protein sources can include tofu, tempeh, chia seeds, and combining foods, like rice and beans. The idea is that eating any more protein than this is simply oxidized for energy or utilized to produce other necessary amino acids. A study done on resistance training subjects supports this idea. The subjects did resistance training and then were given 80g of whey protein. Group one received 10g of protein every 1.5 hours for 8 hours, the second group got 4 servings of 20g of protein every 3 hours, and the third group got 2 servings of 40g of protein every 6 hours. Muscle protein synthesis was highest in those who consumed the protein in 20g portions, and less protein synthesis occurred in the group who consumed 40g of protein at once (Schoenfeld and Aragon). Additional studies support the theory of consuming 25-30g per meal and about 1.6g/kg body weight a day of protein for maximum benefits. The timing of meals should also be taken into account. Americans typically consume much more than 25 grams of protein at lunch and dinner and fall well below the 25g at breakfast. High protein breakfasts are linked to greater satiety throughout the day and reductions in late-night snacking on high carb and fat meals (Leidy). This information concludes that eating as much protein as possible is not beneficial for muscle growth or weight loss, but that eating more protein than the current RDA, about 1.6 g/kg body weight, does provide benefits in terms of muscle growth.
Long-term Effects of a High Protein Diet
Although high protein diets have been proven to have benefits, doctors are still unsure of the long-term effects that high protein diets have on the body. There is currently no upper limit regarding protein, due to insufficient evidence. The main concern of high protein is kidney damage. In those with kidney dysfunction, a high protein diet has been proven to be unsafe. Individuals with chronic kidney disease should consume .6-.75g/kg body weight of protein (Cuenca-Sánchez). Concerning healthy individuals and kidney function, the more protein, the higher excretion of urea and nitrogenous wastes, resulting in higher hydration needs. While this topic needs more research, those at risk of renal diseases, such as individuals with diabetes, hypertension, and CVD should talk to their doctor before beginning a high protein diet (Cuenca-Sánchez). Multiple disease states have been proven to require higher protein needs, such as hemodialysis, hepatitis, cancer, bone marrow transplant, inflammatory bowel disease, and pressure injuries, as well as pregnant women and the elderly (Raymond). If diagnosed with one of these diseases, your doctor will give specific instructions on how much protein to consume. High protein diets in healthy individuals also have other risks. One is nutrient deficiencies. If an individual’s diet consists mostly of protein, and fruits, vegetables, and whole grains are not a focus, they may not get all the necessary micronutrients. High saturated fat intake is also a risk of high protein diets. Many high protein foods, specifically meats, such as beef, lamb, pork, processed meats, and whole fat dairy products contain high levels of saturated fat. High saturated fat intake increases your risk of cardiovascular disease and stroke (Rabin).
What does this mean for the average person?
Perhaps you will think twice before spending loads of money on protein supplements after reading this blog. While consuming enough protein is important, most people can get more than enough just through whole foods, without the need for supplementation. A small number of people do have increased protein needs, like pregnant women, certain individuals with chronic disease or trauma, the elderly, and some athletes. Focus on adding a protein source to each meal throughout the day, and you should have no issues meeting your protein needs. This may include adding foods such as Greek yogurt, eggs, lean meats, nuts, seeds, and fish. If you find you do not eat a variety of high protein foods, then protein powder supplements can be an easy and effective way to meet your needs and can be taken with water, milk, or milk substitutes or be added to smoothies and other baked items. In conclusion, the healthiest diets are those that emphasize all macro and micronutrients, so there is no need to overdo the protein, especially if it’s in place of fats and carbs.
Written by Carley Higgins
Approved and Edited by Supriya Lal, RD, MPH
References
Cuenca-Sánchez, Marta, et al. “Controversies Surrounding High-Protein Diet Intake: Satiating Effect and Kidney and Bone Health.” Advances in Nutrition, vol. 6, no. 3, 2015, pp. 260–266., https://doi.org/10.3945/an.114.007716.
Leidy, Heather J, et al. “The Role of Protein in Weight Loss and Maintenance.” The American Journal of Clinical Nutrition, vol. 101, no. 6, 2015, https://doi.org/10.3945/ajcn.114.084038.
Pasiakos, Stefan M., et al. “The Effects of Protein Supplements on Muscle Mass, Strength, and Aerobic and Anaerobic Power in Healthy Adults: A Systematic Review.” Sports Medicine, vol. 45, no. 1, 2014, pp. 111–131., https://doi.org/10.1007/s40279-014-0242-2.
“Protein Supplements Market Size Report, 2021-2030.” Protein Supplements Market Size Report, 2021-2030, Feb. 2022, https://www.grandviewresearch.com/industry-analysis/protein-supplements-market.
Rabin, Roni Caryn. “Can You Get Too Much Protein?” The New York Times, The New York Times, 6 Dec. 2016, https://www.nytimes.com/2016/12/06/well/eat/can-you-get-too-much-protein.html?_r=1.
Raymond, Janice L., et al. Krause and Mahan's Food & the Nutrition Care Process. Elsevier, 2021.
Schoenfeld, Brad Jon, and Alan Albert Aragon. “How Much Protein Can the Body Use in a Single Meal for Muscle-Building? Implications for Daily Protein Distribution.” Journal of the International Society of Sports Nutrition, vol. 15, no. 1, 2018, https://doi.org/10.1186/s12970-018-0215-1.