Protein is a vital ingredient for a healthy body, regardless of whether you are active or not.
It’s your go-to nutrient to repair damaged cells, boost your immune system and metabolic rate, and create a general feeling of wellness.
There are numerous benefits from having a protein-rich diet:
- It aids muscle growth and recovery. Eating adequate amounts of protein helps you maintain your muscle mass and promotes muscle growth when you do strength training. Numerous studies show that eating plenty of protein can help increase muscle mass and recovery. 1
- It helps boost metabolism through increased fat burning. Eating can boost your metabolism for a short while as your body uses calories to digest foods and make use of the nutrients. This is referred to as the thermic effect of food (TEF). Protein has a much higher thermic effect than other macronutrients — 20–35% compared to 5–15% for fat or carbs. 2
- It supports a weight loss program. Because a high-protein diet boosts metabolism and leads to an automatic reduction in calorie intake and cravings due to its high satiety levels, many people who increase their protein intake tend to lose weight almost instantly. 3 One study found that overweight women who ate 30% of their calories from protein lost 11 pounds (5 kg) in 12 weeks — though they didn’t intentionally restrict their diet. 4
- It helps to reduce cravings and overeating. Increased protein intake has been shown to significantly reduce cravings and overeating. One study in overweight men showed that increasing protein to 25% of calories reduced cravings by 60% and the desire to snack at night by half. 5
There are a huge number of benefits to including protein in your diet, but, like all good things, it is possible to have too much. In this article, we take a closer look at how much protein is too much and how to get the balance right.
Getting the balance right – how much protein should you be getting?
The Recommended Daily Allowance for protein for the average sedentary person is 0.36 grams of protein per pound of body weight (World Health Organisation 2002 6). This is the minimum amount of protein required to prevent malnutrition.
This amounts to:
- 56 grams per day for the average sedentary man.
- 46 grams per day for the average sedentary woman.
Getting enough protein allows important bodily functions to occur, such as the transport of vital molecules such as oxygen around the body, a boosted immune system, and the transmission of messages from cell to cell.
The RDA for protein varies, depending on factors such as age, gender, and activity levels.
For example, studies show that active people need to consume approximately 0.73 grams per pound of body weight to help increase and maintain muscle mass. 7
How much protein is too much?
There is not an official number for too much protein in a diet.
However, experts suggest that you should not eat more than 1g per pound of body weight. 8 People can generally consume this amount of protein, longterm, without seeing any significant side effects. Athletes are advised to eat this amount to maintain optimal muscle mass.
Additional protein over this amount does not offer any benefits and can impose a metabolic burden on the bones, kidneys, and liver.
What happens if you eat too much protein?
As with all nutrients, consuming high amounts of protein over a long period, has its risks. According to research, overconsumption may lead to an increased risk of certain health complications.
- Weight gain. Excess protein consumed is usually stored as fat, while your body excretes the surplus in amino acids. Over time, this can lead to weight gain, especially if you consume too many calories while trying to increase your protein intake. A 2016 study found that weight gain was significantly associated with diets where protein replaced carbohydrates, but not when it replaced fat.
- Bad Breath. Eating high amounts of protein can lead to bad breath, especially if your carbohydrate intake is restricted at the same time. This could be explained by the fact that your body goes into a metabolic state of Ketosis during high protein – low carbohydrate diets. This produces chemicals that give off an unpleasant, fruity smell.
- Constipation. High protein diets that restrict carbohydrate intake, can often be low in fiber. Fiber is needed to keep your digestive system regular, so a deficiency in this nutrient can lead to constipation. 9
- Heart disease. Turning to red meat and full-fat dairy products primarily for your protein intake can lead to health problems like heart disease. This can be related to higher intakes of saturated fats and cholesterol. According to a 2010 study, eating large amounts of red meat and high-fat dairy was shown to increase the risk of coronary heart disease in women. Eating poultry, fish, and nuts lowered the risk. 10
Here’s how you can include the optimum amount of protein in your balanced diet
For most healthy people, a high-protein diet generally isn’t harmful and if you want to maintain a high protein diet, you can. Here are some of our suggestions to ensure you’re being as healthy as possible.
- Find out from your doctor if you have any underlying health conditions (such as kidney disease) that a high-protein diet would be detrimental to
- Spread your protein consumption across all of your meals throughout the day rather than ingesting most of your protein in one meal
- Choose a well-balanced diet that includes all of the macronutrients you need to maintain a healthy lifestyle
- Choose healthy sources of protein such as plant-based protein, whey isolate, pea, brown rice, and soy protein
1 Pasiakos SM, McLellan TM, Lieberman HR. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review. Sports Med. 2015;45(1):111‐131. doi:10.1007/s40279-014-0242-2
2 Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004;23(5):373‐385. doi:10.1080/07315724.2004.10719381
3 Paddon-Jones D, Westman E, Mattes RD, Wolfe RR, Astrup A, Westerterp-Plantenga M. Protein, weight management, and satiety. Am J Clin Nutr. 2008;87(5):1558S‐1561S. doi:10.1093/ajcn/87.5.1558S
4 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
5 Leidy HJ, Tang M, Armstrong CL, Martin CB, Campbell WW. The effects of consuming frequent, higher protein meals on appetite and satiety during weight loss in overweight/obese men. Obesity (Silver Spring). 2011;19(4):818‐824. doi:10.1038/oby.2010.203
6 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/
7 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
8 Delimaris I. Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. ISRN Nutr. 2013;2013:126929. Published 2013 Jul 18. doi:10.5402/2013/126929
9 Bae SH. Diets for constipation. Pediatr Gastroenterol Hepatol Nutr. 2014;17(4):203‐208. doi:10.5223/pghn.2014.17.4.203