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TOPIC: What is the max protein absorbed from one meal?

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March 20, 2012 3:11 PM
This was the question of this

But I thought that people would assume it was one of the huge number of people who keep asking if it is bad to be over their protein allowance, so I reposted with this title. So what is the maximum amount of protein that can be absorbed from one meal, or is there one?
July 27, 2012 1:58 PM
I would like to know the answer to this myself. I have heard it was 30 grams, but have been told that is a myth. What gives?
July 27, 2012 2:02 PM
Depends on many factors, giving a number such as 30 grams is overly simplistic.

Good article on this subject, the intermittent fasting example gives you someting to think about.


A longstanding belief in fitness circles is that the body can only use a certain amount of protein per meal, and the excess is either oxidized or excreted. The ballpark range thrown around is 20-30 grams, with 30 grams being perhaps the most common figure.

This guideline has led many trainees to go through the pains of consuming multiple doses of protein throughout the day, banking that it will maximize muscle anabolism or muscle retention.

Well, true or not, this concept fits in nicely with another longstanding fitness “rule” that you have to eat at least six times per day in order to keep the body’s metabolism revving high. Since the meal frequency and metabolism dogma has been thoroughly debunked [1-5], it’s time to dig into the topic of whether there’s a limit to effective protein dosing, and if so, what that limit might be.

Looking at simple logic first

Let’s imagine an experiment involving two relatively lean 200 lb individuals. For the purposes of this illustration, I’ll assign a daily amount of protein known to adequately support the needs of the athletic population. We’ll give Person A 150 g protein spread over five meals at 30 g each. We’ll give Person B the same amount of protein, but in a single meal. Let’s say that this meal consists of a 16 oz steak, chased with a shake containing two scoops of protein powder.

If we really believed that only 30 g protein can be handled by the body in a single meal, then Person B would eventually run into protein deficiency symptoms because he supposedly is only absorbing a total of 30 g out of the 150 g we’re giving him. At 30 g/day, he’s only getting 0.33 g/kg of bodyweight, which isn’t even half of the already-low RDA of 0.8 g/kg. If the body worked this way, the human species would have quickly become extinct. The human body is more efficient and effective than we give it credit for.

The body will take all the sweet time it needs to effectively digest and absorb just about whatever dose you give it. Person A will have shorter digestion periods per meal in order to effectively absorb and utilize the small meals. Person B will have a longer digestion period in order to effectively absorb and utilize the large meal. While the truth in this logic seems self-evident, the important question is whether or not it’s supported by scientific research. Let’s look at the evidence, starting with immediate-effect (acute) studies, then move on to the longer-term trials.

Research examining speed of absorption

A thorough literature review by Bilsborough and Mann compiled data from studies by various investigators who measured the absorption rates of various protein sources [6]. Oddly, an amino acid mixture designed to mimic the composition of pork tenderloin made the top spot, at 10 g/hour, while whey took a close second at 8-10 g/hour. Other proteins fell in their respective spots below the top two, with little rhyme or reason behind the outcomes. As a matter of trivia, raw egg protein was the most slowly absorbed of them all at 1.3 g/hour.

It’s important to note that these data have some serious limitations. A major one is the variance of the methods used to determine the absorption rates (i.e., intravenous infusion, oral ingestion, ileal ingestion). Most of the methods are just too crude or far-fetched for serious consideration. Another limitation is that these figures could be skewed depending upon their concentration in solution, which can affect their rate of gastric evacuation. Another factor to consider is the timing of ingestion relative to exercise and how that might differentially affect absorption rates. Finally, short-term data leaves a lot open to question.

Short-term research supporting the magic limit

I’ve heard many folks parrot that the maximal anabolic effect of a single protein dose is limited to 20 grams, citing recent work by Moore and colleagues [7]. In this study’s 4-hour post-exercise test period, 40 g protein did not elicit a greater anabolic response than 20 g. I’d interpret these outcomes with caution. Fundamentally speaking, protein utilization can differ according to muscle mass. The requirements of a 140-lb person will differ markedly from someone who’s a lean 200. Additionally, a relatively low amount of total volume was used (12 sets total). Typical training bouts usually involve more than one muscle group and are commonly at least double that volume, which can potentially increase the demand for nutrient uptake. Finally, the conclusion of the authors is questionable. They state explicitly,

“…we speculate that no more than 5-6 times daily could one ingest this amount (~20 g) of protein and expect muscle protein synthesis to be maximally stimulated.”

So, they’re implying that 100-120 grams of protein per day is maximal for promoting muscle growth. Wait a minute, what? Based on both the bulk of the research evidence and numerous field observations, this is simply false [8,9].

In another recent study, Symons and colleagues compared the 5-hour response of a moderate serving of lean beef containing 30 g protein with a large serving containing 90 g protein [10]. The smaller serving increased protein synthesis by approximately 50%, and the larger serving caused no further increase in protein synthesis, despite being triple the dose. The researchers concluded that the ingestion of more than 30 g protein in a single meal does not further enhance muscle protein synthesis. While their conclusion indeed supports the outcomes of their short-term study, it’s pretty easy to predict the outcomes in muscle size and strength if we compared a total daily protein dose of 90 g with 30 g over a longer trial period, let alone one involving a structured exercise protocol. This brings me to the crucial point that acute outcomes merely provide grounds for hypothesis. It’s not completely meaningless, but it’s far from conclusive without examining the long-term effects.

Longer-term research challenging the magic limit

If we were to believe the premise that a 20-30 g dose of protein yields a maximal anabolic effect, then it follows that any excess beyond this dose would be wasted. On the contrary, the body is smarter than that. In a 14-day trial, Arnal and colleagues found no difference in fat-free mass or nitrogen retention between consuming 79% of the day’s protein needs (roughly 54 g) in one meal, versus the same amount spread across four meals [11].

Notably, this study was done on young female adults whose fat-free mass averaged 40.8 kg (89.8 lb). Considering that most non-sedentary males have considerably more lean mass than the female subjects used in the aforementioned trial, it’s plausible that much more than 54 g protein in a single meal can be efficiently processed for anabolic and/or anti-catabolic purposes. If we extrapolated the protein dose used in this study (79% of 1.67g/kg) to the average adult male, it would be roughly 85-95 g or even more, depending on just how close someone is to the end of the upper limits of muscular size.

When Arnal and colleagues applied the same protocol to the elderly population, the single-dose treatment actually caused better muscle protein retention than the multiple-dose treatment [12]. This raises the possibility that as we age, larger protein feedings might be necessary to achieve the same effect on protein retention as lesser amounts in our youth.

IF research nailing the coffin shut?

Perhaps the strongest case against the idea of a dosing limit beyond which anabolism or muscle retention can occur is the recent intermittent fasting (IF) research, particularly the trials with a control group on a conventional diet. For example, Soeters and colleagues compared two weeks of IF involving 20-hour fasting cycles with a conventional diet [13]. Despite the IF group’s consumption of an average of 101 g protein in a 4-hour window, there was no difference in preservation of lean mass and muscle protein between groups.
In another example, Stote and colleagues actually reported an improvement in body composition (including an increase in lean mass) after 8 weeks in the IF group consuming one meal per day, where roughly 86 g protein was ingested in a 4-hour window [14]. Interestingly, the conventional group consuming three meals spread throughout the day showed no significant body composition improvements.

Keep in mind that bioelectrical impedance (BIA) was used to determine body composition, so these outcomes should be viewed with caution. I’ve been highly critical of this study in the past, and I still am. Nevertheless, it cannot be completely written off and must be factored into the body of evidence against the idea of a magic protein dose limit.

Conclusion & application

Based on the available evidence, it’s false to assume that the body can only use a certain amount of protein per meal. Studies examining short-term effects have provided hints towards what might be an optimal protein dose for maximizing anabolism, but trials drawn out over longer periods haven’t supported this idea. So, is there a limit to how much protein per meal can be effectively used? Yes there is, but this limit is likely similar to the amount that’s maximally effective in an entire day. What’s the most protein that the body can effectively use in an entire day? The short answer is, a lot more than 20-30 g. The long answer is, it depends on several factors. In most cases it’s not too far from a gram per pound in drug-free trainees, given that adequate total calories are provided [8,9].

In terms of application, I’ve consistently observed the effectiveness of having approximately a quarter of your target bodyweight in both the pre- and post-exercise meal. Note: target bodyweight is a surrogate index of lean mass, and I use that to avoid making skewed calculations in cases where individuals are markedly over- or underweight. This dose surpasses the amounts seen to cause a maximal anabolic response but doesn’t impinge upon the rest of the day’s protein allotment, which can be distributed as desired. On days off from training, combine or split up your total protein allotment according to your personal preference and digestive tolerance. I realize that freedom and flexibility are uncommon terms in physique culture, but maybe it’s time for a paradigm shift.

In sum, view all information – especially gym folklore and short-term research – with caution. Don’t buy into the myth that protein won’t get used efficiently unless it’s dosed sparingly throughout the day. Hopefully, future research will definitively answer how different dosing schemes with various protein types affect relevant endpoints such as size and strength. In the mean time, feel free to eat the whole steak and drink the whole shake, and if you want to get the best bang for your buck, go for a quality protein blend such as Nitrean!
Edited by Hendrix7 On July 27, 2012 2:03 PM
July 27, 2012 2:03 PM
Where's Tigersword?

The max would be all of it.
July 27, 2012 2:32 PM
Here's another article by Tom Venuto:

Thirty grams of protein per meal seems to have become one of those "nutrition rules of thumb" that has been passed around so long that it has become accepted as an "unbreakable nutrition law." Some people claim that the human body can only digest 30 grams of protein per sitting (others claim the limit is 40 grams).

There has been a lot of research done on protein needs, although not much of it has focused specifically on the maximum amount digestible per meal. There have been studies where a large bolus of protein was eaten at one time rather than in small, frequent meals, and yet positive nitrogen balance was achieved. This would suggest that the 30 grams per meal limit does not exist and that 60 grams over three meals would allow your body to utilize the majority of that 180 grams.

30-40 grams per meal may be a pretty good rule of thumb for bodybuilding diets with an eating frequency of 5-6 small meals per day (slightly less for females). However, I have never found any research which says that the body has a "30 grams at a time" absolute limit and it doesn't seem likely that one fixed amount could apply to every person in every situation, with no accounting for body weight and activity level.

Nutritional needs - including protein - are highly variable depending on the individual. For example, are the protein needs for a 250-pound bodybuilder the same as a 105-pound ballerina? Are they the same for a 17-year-old football player and a sedentary 70-year-old? The obvious answer is no, and this is why you should look at dietary recommendations made as "absolutes" with caution. Instead, it's optimal to think in terms of customization for each individual.

The best way to figure out how much protein you need in one sitting is to first calculate your total daily protein needs. One gram per pound of bodyweight is a common recommendation (for active, strength-trained individuals), although total protein needs should be customized according to age, gender, body size, lean body mass, activity levels, energy status (deficit or surplus) and personal goals. Then take your daily needs and divide that amount by the number of meals you eat each day; usually five or six in a bodybuilding-style nutrition program.

As a bodybuilder or someone participating in regular strength training, the one gram per pound of bodyweight guideline is a pretty good estimate for daily protein needs (although some competitive bodybuilders go as high as 1.25 to 1.5 grams per pound on reduced carb pre-contest diets). If you weigh 180 pounds and you’re eating six times per day, then bingo – there’s your 30 grams. (180 grams divided by 6 meals). If you’re a 240-pound male bodybuilder, and you eat six times per day, now you’re up to 40 grams per meal.

If you’re a 125 pound female athlete, then 125 grams a day would suffice; spread over 5 meals a day, that’s 25 grams per meal. On a pre contest fitness or figure competition diet, many women eat up to 150-175 grams of protein per day, which, over five meals, is 30-35 grams per meal.

Some people think that the 30 grams of protein "rule" was started by protein supplement company marketing because thats the amount of protein they put into each serving of their product. However, looking at these examples, you can see that 30-35 grams of protein per meal is pretty close to the average amount that's consumed on a typical bodybuilding diet. My belief is that this is where the 30-gram "rule" came from - it's simply an average figure. But just because the "average" comes out to around 30 grams per meal, doesn’t mean that 30 grams is the most that you can digest.

The digestibility rate of high quality protein sources is 94 to 97% and even the protein in grains and beans is 78-85% digestible. Generally what happens with a large meal, including a large protein intake, is that the meal will simply take longer to digest, but the body will increase the rate of gastric emptying and nutrient absorption in response to the larger food intake. So while the 5 or 6 small meals a day is an accepted practice among bodybuilders, there doesn't seem to be any proof that you couldn't utilize the protein if you took it across only 3 meals instead.

On the other hand, if the total amount of protein exceeds what your body requires and if you are in a caloric surplus, you can convert the excess into body fat. Although protein is the least likely of the macronutrients to be converted to fat (due to an energy inefficient conversion process), a caloric surplus will always lead to fat deposition, even if the surplus comes from protein. In a caloric deficit, protein consumed beyond the body's needs for skeletal muscle and body tissue protein synthesis can be converted to glucose through a process called gluconeogensis.

Bottom line: Even large protein servings can be digested and absorbed, and it appears there is no 30 gram absolute limit. On the other hand, huge servings of protein at one time are not necessary for muscle growth. Beyond what is needed for growth, repair and energy, an excess of protein can get "wasted" if you are referring to being stored as fat or burned for energy.

1. Plant proteins in relation to human protein and amino acid nutrition. Young V. and Pellet P., American Journal of clinical Nutrition. 59. pp 1203S-1202S. 1994

2. Protein pulse feeding improves protein retention in elderly women. Arnal, M, et al. American Journal of clinical Nutrition. 69. 1202-1208. 1999
July 27, 2012 2:57 PM
"These studies have found that eating high-quality protein after a training session enhances
protein synthesis during the recovery period. A worthwhile effect is achieved with as little as 10 g of protein,
while the maximal effect occurs with the intake of 20-25 g of protein"
July 27, 2012 6:25 PM
bump for all the articles because I'm being ADD now.
September 12, 2013 1:07 PM
I would also imagine that age probably factors somewhere in the figures. Honestly there are so many variables to consider its like trying to figure out why someone has a cold. Hell temperature, metabolism, heart rate, chemicals released from the brain, you name it anything can be factored into results. We only come to the conclusion something is fact when it fits more people then it doesn't. Before i got serious about my diet i ate 1 time a day about 900 calories, consuming no more then 70 grams of protein at best. Slept only 5hrs a night, up playing world of warcraft. And for some reason my body was still at least maintaining my muscle. I have also been tested with a much higher T level then an average male. Bottom line is, people have their theories, you can only look at them for guidance because in the end we are all different in small ways. I just learned what worked for me.
September 12, 2013 1:29 PM
Bump for debunking bro-science. :)
September 12, 2013 1:55 PM
Depends on how much you swallow
September 12, 2013 1:56 PM
According to Layne Norton (PhD in protein metabolism) you can absorb any amount of protein within reason........but the the max for utilization for anabolic response seems to get maxed out at 30-40 grams.

BioLayne Video Log 4 - Myths About Protein
September 12, 2013 2:11 PM
One other thing to consider:

Let's just say for the sake of example that I ate a pound of chicken breast as part of my dinner. It takes time to digest all of that and get the amino acids in my bloodstream. How many hours do you think they would be in good and constant supply?
September 12, 2013 2:25 PM
The "30g" rule, in its basic form, is inconsistent with our evolutionary development, so I'm not inclined to put much stock in it until someone actually proves it.

That said, I could see something that (effectively) bypasses certain digestive feedback mechanisms - something like a protein shake - having a limit somewhere in this range.

But for real food? I am highly sceptical.


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