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’s used to build and maintain muscle and to replenish the amino acid supply used to make enzymes, hormones, and other tissues besides muscle.2

For adults with diabetes, obesity, and other metabolic issues, we recommend eating a low-carb diet that is moderate in protein. This goes for all levels of carb reduction.
 

Moderate protein intake

We define “moderate” protein as roughly 1.2 to 1.7 grams per kilogram (g/kg) of reference body weight per day for adults.3 As an example, if your reference body weight is 143 lbs (65 kg), you need about 78 to 111 grams of protein per day.

You can use these target protein range tables to estimate your reference body weight and how much protein you should aim for each day. For most people, this is between 70 and 140 grams per day. For most “protein foods,” one ounce equals about 7 grams of protein.

As an example, you can get about 100 grams of protein by eating three eggs and an ounce (30 grams4) of cheese at breakfast, 4 to 5 ounces (120 to 150 grams) of fish at lunch, and 5 ounces (140 grams) of meat at dinner. Please see additional ideas for meeting your protein needs in our complete protein guide.

Moderate protein intake 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.5

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.6 In fact, most people can probably build muscle with a protein intake of no more than 1.6 g/kg/day.7

Additionally, gram for gram, protein is considerably more expensive than natural fats like butter, olive oil and coconut oil.8  

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.9

Lacto-ovo vegetarian keto diets are definitely an option, and even vegan low-carb diets are possible. However, consistently meeting protein needs can be challenging for vegans, especially those who eat very-low-carb or ketogenic diets.10

 

Protein intake per meal

In addition to the daily amount of protein, it’s important to consider the amounts consumed at meals. Because there appears to be a limited amount of protein that can be absorbed at a meal, it may be best to evenly space out your protein throughout the day, if possible.11

It’s possible that if you eat much more protein than your body can absorb, the resulting excess amino acids may instead be used for gluconeogenesis (literally “making new glucose”).12 Protein may also raise insulin levels when consumed in large amounts.13 However this has not been shown to be a clinically significant problem in the setting of a low-carb diet.14

In fact, well-conducted physiological studies show that protein is not a meaningful contributor to blood glucose either in healthy people or people with type 2 diabetes.15 One study showed even a meal with 50 grams of protein didn’t cause a significant increase in blood sugar.16

 

Summary

For the reasons listed above, we recommend a moderate protein intake of roughly 1.2 to 1.7 grams per kilogram (g/kg) of reference 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/kg/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. Food and Function 2016: Dietary protein intake and human health [overview article; ungraded]

  3. “Reference body weight” is a rough approximation of your lean body mass – the part that needs protein – rather than total body weight.

  4. The “grams” here refers to the total grams of the food, not the protein grams

  5. 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 and body composition:

    British Journal of Nutrition 2020: The effect of 12 weeks of euenergetic high-protein diet in regulating appetite and body composition of women with normal-weight obesity: a randomised controlled trial [randomized trial; moderate evidence]

    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 optimal metabolic function:

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

  6. 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]

    The following review recommends 2.3-3.1 g/kg/day of protein for body builders.

    Journal of the International Society of Sports Nutrition 2014: Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation/strong> [overview article; ungraded]

    The following review explains the increased protein requirements for burn victims

    Burns and Trauma 2017: Nutrition and metabolism in burn patients [overview article; ungraded]

  7. 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]

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

  9. 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]

  10. Although the quality of protein in different legumes varies, many appear to be about 20-50% less digestible than animal protein:

    Food Science and Nutrition 2017: Determination of the protein quality of cooked Canadian pulses [mechanistic study; ungraded]

  11. The precise amount of protein 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 result in 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]

  12. 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]

  13. 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]

  14. In a recent presentation, Dr. Ben Bikman proposed that your body’s ability to regulate blood sugar and insulin after you eat protein is influenced mainly by your carb intake, as well as how metabolically healthy you are.

    Overall, he’s observed that those who eat keto or very low carb aren’t affected by high protein intake the way people on high-carb diets are. Therefore, although protein triggers a glucose and insulin response, this is unlikely to be a clinical concern for most people.

  15. Diabetes 2013: Dietary proteins contribute little to glucose production, even under optimal gluconeogenic conditions in healthy humans. [nonrandomized, weak evidence]

  16. Journal of Clinical Endocrinology and Metabolism 2001: Effect of protein ingestion on the glucose appearance rate in people with type 2 diabetes [randomized trial; moderate evidence]