Protein is an essential macronutrient found in every cell in the body. 1
It is your go-to-nutrient to repair damage to cells, boost your immune system and metabolic rate, and create a general feeling of wellness. Proteins play a role in:
- Transporting molecules throughout the body 2
- Helping repair cells and make new ones 3
- Protecting the body from viruses and bacteria 4
- Promoting proper growth and development in children, teenagers, and pregnant women 5
Proteins are made out of smaller molecules called amino acids, which are linked together in a long strand. Some of these amino acids can be produced by your body, but others need to be ingested through your diet. The latter are called essential amino acids.
Without having the right amount of protein in your diet, you run the risk of missing out on those key functions. Eventually, that could lead to problems, such as a loss of muscle mass, failure to grow, and weakened functioning of the heart and lungs. 6
How much do you need each day?
The RDA (Recommended Daily Allowance) is 0.36 grams of protein per pound of body weight , according to the World Health Organisation (2002). 7
This amounts to:
- 56 grams per day for the average sedentary man.
- 46 grams per day for the average sedentary woman.
The right amount of protein for any one individual depends on many factors, including their activity levels, age, muscle mass, physique goals, and current state of health.
In this article, we take a look at the optimal amounts of protein and how lifestyle factors such as weight loss, muscle building, and activity levels factor in.
Ensuring you are getting enough protein during a weight loss program is crucial. Protein is one of the key factors in a diet that increases a person’s ability to lose weight.
What’s more, high-protein diets have been shown to help reduce body fat, especially around the belly and increase lean muscle mass. 8
During weight loss, protein has 4 main benefits:
- An increased level of slow-burning energy
- High satiety levels, helping you feel fuller for longer 9
- A high thermic effect of food, meaning your body needs to burn more energy to process protein than either fat or carbohydrates
- Increased muscle mass, leading to a higher fat burn 10
It’s important to make sure you are choosing the right protein for your goals. For example, whey isolate is more likely to help with weight loss than other types of protein.
In a recent study, overweight and obese adults took 56 grams of whey protein daily for 23 weeks and lost 5 pounds (2.3 kg) without changing anything else in their diet. 11
According to studies, 12 a protein intake of around 30% of calories may be optimal for weight loss. This amounts to 150 grams per day for someone on a 2000-calorie diet.
And that’s not all. Protein has been proven to help prevent weight gain in the first place.
In one study, a modest increase in protein from 15% to 18% of calories reduced the number of overweight people who regained after weight loss by 50%. 13
Muscles are a dynamic tissue in your body and are constantly being broken down and rebuilt. To gain muscle your body must synthesize more muscle protein than it builds.
For this reason, people who want to build muscle, need to eat greater amounts of protein than others, alongside their weight lifting and resistance training. 14
When dieting, it is common for muscle to be lost as well as fat. To prevent this, it’s important to eat large amounts of protein. 15
A common recommendation for protein intake when building muscle is about 1g per pound of body weight.
Recent studies have found that people who follow a weight training program need to consume approximately 0.73 grams per pound of body weight to help increase and maintain muscle mass. 16
Other Circumstances that increase protein needs
Aside from having specific physique and muscle mass goals, people who are more active in their everyday life will need more protein than those who are sedentary.
If your job is physically demanding, or you do a lot of exercise including walking, running, and swimming, you will need more protein.
In a position paper released by the International Society of Sports Nutrition, it is recommended that those who engage in cardiovascular exercises, such as runners should eat up to 1g of protein per pound of body weight. 17
Recent studies suggest that older adults need to consume more protein. One study recommended that elderly adults need to eat between 0.5 and 0.65g of protein per pound of body weight to help protect against some of the health risks of aging. 18
Studies also show that pregnant women need to consume more than the average amount of protein as pregnancy has been shown to complicate the metabolism of amino acids. In a study carried out by the US Institute of Medicine, it is estimated that pregnant women need to consume on average 10g of protein more than their Recommended Daily Allowance (RDA) throughout their pregnancy. 19
How to ensure you’re getting enough protein
Protein can be found in many food sources, including meat, fish, eggs, and dairy products.
For those looking to increase their protein intake, but who struggle to find the time for meal prep and cooking, protein bars can be a great way to ensure you are getting enough protein.
The average protein bar contains anywhere between 10g – 30g of protein per serving, which is a helpful boost when trying to hit your RDA or your personal recommended protein intake.
1 National Academy of Sciences, Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academy Press. Washington, DC, 2005. www.nal.usda.gov/sites/default/files/fnic_uploads/energy_full_report.pdf.
2 Cooper GM. The Cell: A Molecular Approach. 2nd edition. Sunderland (MA): Sinauer Associates; 2000. Transport of Small Molecules. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9847/
3 Kreider RB, Campbell B. Protein for exercise and recovery. Phys Sportsmed. 2009;37(2):13‐21. doi:10.3810/psm.2009.06.1705
4 University of Utah Health Sciences. (2012, April 2). How key protein protects against viral infections. ScienceDaily. Retrieved June 12, 2020 from www.sciencedaily.com/releases/2012/04/120402093151.htm
5 Carbone JW, Pasiakos SM. Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. Nutrients. 2019;11(5):1136. Published 2019 May 22. doi:10.3390/nu11051136
6 Campbell WW, Trappe TA, Jozsi AC, Kruskall LJ, Wolfe RR, Evans WJ. Dietary protein adequacy and lower body versus whole body resistive training in older humans. J Physiol. 2002;542(Pt 2):631‐642. doi:10.1113/jphysiol.2002.020685
7 Joint WHO/FAO/UNU Expert Consultation. Protein and amino acid requirements in human nutrition. World Health Organ Tech Rep Ser. 2007;(935):. https://www.who.int/nutrition/publications/nutrientrequirements/WHO_TRS_935/en/
8 Halkjaer J, Tjønneland A, Thomsen BL, Overvad K, Sørensen TI. Intake of macronutrients as predictors of 5-y changes in waist circumference. Am J Clin Nutr. 2006;84(4):789‐797. doi:10.1093/ajcn/84.4.789
9 Holt SH, Miller JC, Petocz P, Farmakalidis E. A satiety index of common foods. Eur J Clin Nutr. DOI:1995;49(9):675‐690.
10 Carbone JW, Pasiakos SM. Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. Nutrients. 2019;11(5):1136. Published 2019 May 22. doi:10.3390/nu11051136
11 Weigle DS, Breen PA, Matthys CC, et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005;82(1):41‐48. doi:10.1093/ajcn.82.1.41
12 Weigle DS, Breen PA, Matthys CC, et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005;82(1):41‐48. doi:10.1093/ajcn.82.1.41
13 Westerterp-Plantenga MS, Lejeune MP, Nijs I, van Ooijen M, Kovacs EM. High protein intake sustains weight maintenance after body weight loss in humans. Int J Obes Relat Metab Disord. 2004;28(1):57‐64. doi:10.1038/sj.ijo.0802461
14 Bosse JD, Dixon BM. Dietary protein to maximize resistance training: a review and examination of protein spread and change theories. J Int Soc Sports Nutr. 2012;9(1):42. Published 2012 Sep 8. doi:10.1186/1550-2783-9-42
15 de Souza RJ, Bray GA, Carey VJ, et al. Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial. Am J Clin Nutr. 2012;95(3):614‐625. doi:10.3945/ajcn.111.026328
16 Morton RW, Murphy KT, McKellar SR, et al. 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;52(6):376‐384. doi:10.1136/bjsports-2017-097608
17 Campbell, B., Kreider, R.B., Ziegenfuss, T. et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr 4, 8 (2007). https://doi.org/10.1186/1550-2783-4-8
18 Morais JA, Chevalier S, Gougeon R. Protein turnover and requirements in the healthy and frail elderly. J Nutr Health Aging. 2006;10(4):272‐283.
19 Institute of Medicine (US) Committee on Nutritional Status During Pregnancy and Lactation. Nutrition During Pregnancy: Part I Weight Gain: Part II Nutrient Supplements. Washington (DC): National Academies Press (US); 1990. Available from: https://www.ncbi.nlm.nih.gov/books/NBK235228/ doi: 10.17226/1451