How much protein per meal, and does spreading it out matter?

Key takeaways

• The International Society of Sports Nutrition's 2017 position stand gives a general range of 20 to 40 grams of protein per serving. A 2018 review proposes 0.4 grams per kilogram per meal, and a 2023 study found 100 grams in one serving produced a larger and longer response than 25.⁵¹⁴
• In Moore's 2009 study, 6 young men drank 0, 5, 10, 20 or 40 grams of whole egg protein after a leg workout. Over the next 4 hours, muscle protein synthesis was maximally stimulated at 20 grams.²
• In Trommelen's 2023 study, 36 young men drank 0, 25 or 100 grams of milk protein after a whole-body workout. Myofibrillar protein synthesis in muscle was about 20 percent higher with 100 grams than with 25 in the first 4 hours and about 40 percent higher from hour 4 to hour 12.⁴
• On spreading it out, Areta's 2013 study found 20 grams of whey every 3 hours produced more muscle protein synthesis over 12 hours than the same 80 grams taken as 8 servings of 10 or 2 servings of 40. A 2018 review counted that low 80 gram total as a major limitation.³¹
• The review ties its 0.4 grams per kilogram to a daily amount. Across at least 4 meals it adds up to 1.6 grams per kilogram of body weight a day.¹

How much protein per meal?

Two papers put a number on it, and the numbers don't match. The International Society of Sports Nutrition's 2017 position stand gives general recommendations of 0.25 grams of high-quality protein per kilogram of body weight per serving, or 20 to 40 grams. Schoenfeld and Aragon's 2018 review proposes 0.4 grams per kilogram per meal, and up to 0.55 when the day's total is set at the upper figure it found in the literature.⁵¹

The review says where its 0.4 comes from, an analysis that found 0.25 grams per kilogram maximally stimulated muscle protein synthesis in young men, with two standard deviations added on top.¹

Both papers are written about people who train. And the three experiments covered below didn't measure muscle size or body weight. They measured muscle protein synthesis, the rate at which muscle builds new protein, for 4 to 12 hours after a workout and a protein drink.⁵¹²³⁴

What did each protein per meal study measure?

The three experiments below all tested young men after resistance exercise. They differ in the protein used, the amount, and how long the researchers kept measuring.²³⁴

Moore's team had each man come in on 5 separate occasions and take the drinks in random order. After the 20 and 40 gram drinks the men oxidized more leucine, an amino acid, and the authors concluded that protein taken in faster than tissue can use it is oxidized instead. Schoenfeld and Aragon's review adds that the 40 gram dose produced an 11 percent greater absolute increase than the 20 gram dose, a difference that wasn't statistically significant.²¹

Areta's team tested timing instead of dose. The men had at least 2 years of resistance training behind them, and every group took in the same 80 grams of whey over the 12 hours.³

Trommelen's team split the men into 3 groups of 12. They picked 25 grams as the amount proposed as optimal and 100 grams as the largest amount they considered feasible to eat in one meal.⁴

How much protein can your body absorb in one meal?

Taken literally, almost all of it. Schoenfeld and Aragon write that absorption means nutrients passing from the gut into the bloodstream, and that by this definition the amount of protein the body can absorb is virtually unlimited. The open question is how much of one serving goes toward building muscle.¹

The older view was that muscle protein synthesis maxes out in young adults at about 20 to 25 grams of high-quality protein, and that anything above that is oxidized for energy or turned into other compounds.¹

Trommelen's study could follow the protein itself, because the milk protein was produced with a tracer built in. Of the 25 gram drink, 51 percent had reached the bloodstream as amino acids by 4 hours and 66 percent by 12 hours. Of the 100 gram drink, 26 percent had reached it by 4 hours and 53 percent by 12 hours, and the release hadn't leveled off. The authors' reading is that a larger serving needs longer to be digested and absorbed.⁴

Is there a maximum amount of protein per meal?

Trommelen's 2023 study looked for an upper limit and didn't find one within the amounts it tested. Over the full 12 hours, muscle protein synthesis was highest with 100 grams, then 25 grams, then the placebo. Synthesis of myofibrillar protein, one of the muscle protein fractions the study measured, was about 20 percent higher with 100 grams than with 25 during the first 4 hours and about 40 percent higher from hour 4 to hour 12.⁴

Several responses to the 100 gram drink still hadn't returned to baseline when the 12 hours ended, so the authors treat their numbers for that dose as minimum estimates.⁴

The study has limits that its authors spell out. It tested healthy young men after one whole-body workout, and they say they don't know whether the findings extend to other groups or conditions. It covered a single day, and it measured protein synthesis, not muscle gained.⁴

Does spreading protein out matter?

In Areta's study, it did. All three patterns raised muscle protein synthesis above resting levels through the 12 hours. The pattern of 20 grams every 3 hours came out 31 percent above 10 grams every 1.5 hours and 48 percent above 40 grams every 6 hours.³

Later papers questioned how far that result reaches. Schoenfeld and Aragon point out that 80 grams over 12 hours came to less than 1 gram per kilogram of body mass for the men in the study, and that the men took in nothing but whey, a fast-acting protein. The ISSN paper also calls that total quite low. Areta's own team wrote that the long-term effects of eating that way with whole foods still needed study.¹⁵³

Trommelen's study points the other way. One large serving was followed by a response lasting more than 12 hours, and the authors write that larger, less frequent meals are a workable alternative to smaller, more frequent ones.⁴

Longer studies haven't settled it. The 2018 review describes a 2 week study of older women in which eating 79 percent of the day's protein in one meal retained more fat-free mass than spreading it over four meals. It also describes a study in which a high-protein diet eaten as 6 meals a day was the only one of three diets to bring a significant gain in lean mass over the first 28 days. The ISSN paper calls the collective results of studies on protein patterns mixed.¹⁵

Where do the protein per meal studies disagree?

Set side by side, the papers split on four questions. Their designs differ too. They used egg, whey or milk protein, a leg workout or a whole-body one, and a measuring window of 4 hours or 12.²³⁴

What does this mean for your daily protein total?

In Schoenfeld and Aragon's review, the per-meal figure and the daily figure are tied together. The review puts the daily intake that maximizes training gains in muscle and strength at about 1.6 grams per kilogram, at least when people aren't dieting, and 0.4 grams per kilogram across 4 meals is how it gets there. It adds that 1.6 isn't a hard limit, and that more research is needed to pin down an upper per-meal threshold.¹

The ISSN paper gives a daily range of 1.4 to 2.0 grams per kilogram of body weight as enough for most exercising people. It says that once a daily amount is reached, how often and in what pattern the servings are eaten may be a key factor in protein synthesis rates, and that servings should ideally be spaced evenly, every 3 to 4 hours.⁵

What the experiments disagree on is how much the split matters. Areta's result favors even spacing, and Trommelen's shows a large serving still being used more than 12 hours later.³⁴

Daily protein amounts from weight loss studies are in the protein and weight loss guide linked below. A clinician or registered dietitian is the person to ask about your own protein needs.

Worked example

Take a made-up person who weighs 80 kilograms, about 176 pounds. The ISSN's 0.25 grams per kilogram works out to 0.25 times 80, or 20 grams a serving. Schoenfeld and Aragon's 0.4 grams per kilogram works out to 32 grams a meal, and 4 meals of 32 grams come to 128 grams, which is 1.6 grams per kilogram for the day. Their upper figure of 0.55 works out to 44 grams a meal. So for one person, the papers' own per-meal figures run from 20 to 44 grams. That's the papers' math for one body weight, not advice for any one person.⁵¹

A closer look

Trommelen's 2023 paper offers a reason earlier studies saw a ceiling. Earlier dose studies tested 45 grams or less and measured for 6 hours or less, which the authors say is likely too short for a large serving to be fully digested and absorbed. When they measured for 12 hours, amino acid levels in the blood stayed above the placebo group's for 5 hours after 25 grams of milk protein and for the whole 12 hours after 100 grams. Schoenfeld and Aragon's review was published in 2018, before that study.⁴¹

Questions and answers

Related guides

• How much protein to lose weight
• High protein, low calorie foods
• Building muscle in a calorie deficit
• How to count macros
• Protein tracker app
• Lean body mass calculator
• Tracking protein with ChatGPT

Sources

1. Journal of the International Society of Sports Nutrition. Schoenfeld, Aragon. 2018.
2. American Journal of Clinical Nutrition. Moore, Robinson, Fry, Tang, Glover, Wilkinson, Prior, Tarnopolsky, Phillips. 2009.
3. Journal of Physiology. Areta, Burke, Ross, Camera, West, Broad, Jeacocke, Moore, Stellingwerff, Phillips, Hawley, Coffey. 2013.
4. Cell Reports Medicine. Trommelen, van Lieshout, Nyakayiru, Holwerda, Smeets, Hendriks, van Kranenburg, Zorenc, Senden, Goessens, Gijsen, van Loon. 2023.
5. Journal of the International Society of Sports Nutrition. Jäger, Kerksick, Campbell, Cribb, Wells, Skwiat, Purpura, Ziegenfuss, Ferrando, Arent, Smith-Ryan, Stout, Arciero, Ormsbee, Taylor, Wilborn, Kalman, Kreider, Willoughby, Hoffman, Krzykowski, Antonio. 2017.