How much protein should you eat?

Protein is a vital nutrient our bodies need to survive and thrive.1 This is the Diet Doctor policy for how much protein we recommend.

Unlike fat and carbohydrates, protein isn’t used as a primary energy source under normal circumstances. Instead, it is used to build and maintain muscle and to replenish the amino acid supply used to make enzymes, hormones, and other tissues in addition to muscle.

For adults with health issues that could benefit from it, we recommend eating a low-carbohydrate, high-fat diet that is moderate in protein. This goes for all levels of carb restriction.
 

Moderate protein intake

We define “moderate” protein as roughly 1.2 to 1.7 grams per kilogram (g/kg) of ideal body weight per day for adults. As an example, if your ideal body weight is 65 kg (143 lbs), you need about 78 to 111 grams of protein per day.

This protein intake can for example be achieved by eating three eggs at breakfast, 4 to 5 ounces (120 to 150 grams) of fish at lunch, and 5 ounces (140 grams) of beef at dinner. Please see additional ideas for meeting your protein needs in our complete protein guide.

Protein intake within this range has been shown to preserve muscle mass, improve body composition, and provide other health benefits in people who eat low-carb diets or higher-carb diets.2

Although this is at least 50% higher than the minimum Recommended Daily Allowance (RDA) for protein of 0.8 g/kg of body weight, it is less than “high-protein” diets containing more than 2 g/kg of protein per day. These higher levels are likely only beneficial when needs are truly increased, such as healing from major injury or surgery, or for increasing muscle mass for competitive body building.3

Additionally, gram for gram, protein is considerably more expensive than natural fats like butter, olive oil and coconut oil.4  

Protein sources

We recommend that you choose unprocessed meat, poultry, seafood, eggs and/or dairy as protein sources. Consuming animal products helps ensure that you receive all of the essential amino acids your body needs.5

Lacto-ovo vegetarian low-carbohydrate diets are a definitive option, and even vegan low-carbohydrate diets are possible. However, consistently meeting protein and other nutrient needs can be challenging for vegans, in particularly those who eat very-low-carb or ketogenic diets.6  

Protein intake per meal

In addition to the daily amount of protein, we also want to pay some attention to our per meal consumption. There appears to be a limited amount of protein that can be absorbed at a meal, and it may be good to relatively evenly space out the amount of protein throughout the day if possible.7

It is possible that if you eat more protein than your body can absorb, the resulting excess amino acids may instead be used for gluconeogenesis (literally “making new glucose”).8 Protein may also raise insulin levels when consumed in large amounts.9 However, this hasn’t been tested in many people other than in small studies. Protein’s effect on insulin may vary significantly from person to person.
 

Summary

Due to the reasons listed above, we recommend a moderate protein diet of roughly 1.2 to 1.7 grams per kilogram (g/kg) of ideal body weight per day for adults. This is higher than the RDA of 0.8g/kg/d, but lower than “high protein” levels above 2.0gm/kd/d.

/ Franziska Spritzler, RD


Videos about protein

  1. Muscle, hormones, enzymes and other structures in your body are made up of 20 amino acids, the building blocks of protein. Every day, old proteins are broken down. Although most are recycled, a portion needs to replenished with new amino acids, 9 of which are essential, meaning your body can’t make them. These 9 amino acids must come from protein in your diet.

    International Journal for Vitamin and Nutrition Research 2011: Protein turnover, ureagenesis and gluconeogenesis [overview article; ungraded]

  2. Low-carb diets:

    Peer J 2019: Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: a randomised clinical trial [moderate evidence]

    Diabetes Therapy 2018: Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year: an open-label, non-randomized, controlled study [weak evidence]

    Moderate protein diets for weight loss:

    American Journal of Clinical Nutrition 2015: The role of protein in weight loss and maintenance [overview article; ungraded]

    Higher-carb diets:

    Nutrients 2018: Effects of a high-protein diet including whole eggs on muscle composition and indices of cardiometabolic health and systemic inflammation in older adults with overweight or obesity: a randomized controlled trial [moderate evidence]

    The American Journal of Clinical Nutrition 2017: The effects of dietary protein intake on appendicular lean mass and muscle function in elderly men: a 10-wk randomized controlled trial [moderate evidence]

    The Journal of Nutrition 2013: Normal protein intake is required for body weight loss and weight maintenance, and elevated protein intake for additional preservation of resting energy expenditure and fat free mass [randomized trial; moderate evidence]

    For metabolic functions:

    American Journal of Clinical Nutrition 2015: Defining meal requirements for protein to optimize metabolic roles of amino acids [overview article; ungraded]

  3. The RDA is an estimate of the minimum amount of protein needed to meet the needs of 97% of healthy adults:

    Institute of Medicine 2005: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids [overview article; ungraded]

    Most people can probably build muscle well with a protein intake of no more than 1.6 g/kg/day:

    British Journal of Sports Medicine 2018: 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 [strong evidence]

  4. The American Journal of Clinical Nutrition 2010: The cost of US foods as related to their nutritive value [overview article; ungraded]

  5. Although plant protein sources (nuts, seeds) also provide essential amino acids, animal proteins are considered higher quality because they provide all of the essential amino acids in the amounts your body needs. This includes leucine, the main amino acid used to build and maintain muscle.

    American Journal of Clinical Nutrition 2015: Commonly consumed protein foods contribute to nutrient intake, diet quality, and nutrient adequacy [overview article; ungraded]

    Journal of Cachexia, Sarcopenia and Muscle 2017: Dietary protein content for an optimal diet: a clinical view [overview article; ungraded]

    Scientific Reports 2016: Essential amino acids: master regulators of nutrition and environmental footprint? [overview article, ungraded]

  6. Although a carefully planned vegan diet can supply all essential amino acids, because of the decreased bioavailability of these in plant foods, protein needs are approximately 30% higher for those following a vegan diet.

    Brown, Judith 2008: Nutrition through the life cycle [textbook chapter; ungraded]

  7. The precise amount that can be absorbed and used depends on age, muscle mass, meal composition and other factors. However, in one study of both young and older adults, a very high-protein (90 grams) meal didn’t lead to greater muscle protein synthesis than a moderate-protein (30 grams) meal.

    Journal of the American Dietetic Society 2011: Moderating the portion size of a protein-rich meal improves anabolic efficiency in young and elderly [randomized trial; moderate evidence]

  8. Gluconeogenesis is a demand-driven process in which your liver converts amino acids and other compounds into glucose in order to prevent blood glucose from dropping too low. Although gluconeogenesis is a normal process that occurs on a regular basis, it may increase when protein intake is very high.

    Diabetologia 2000: Effect of long-term dietary protein intake on glucose metabolism in humans [non-randomized trial; weak evidence]

    International Journal for Vitamin and Nutrition Research 2011: Protein turnover, ureagenesis and gluconeogenesis [overview article; ungraded]

  9. The American Journal of Clinical Nutrition 1997: An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods [non-randomized trial; weak evidence]