The gut and liver take up a vast majority of the protein consumed; approximately 10% is utilized by muscle. The rest of the protein is catabolized for energy, etc.
How much protein can your body absorb in one day? This article covers protein synthesis (i.e., protein intake), protein absorption, and protein digestion.
HOW MUCH PROTEIN CAN YOUR BODY ABSORB IN ONE MEAL SUMMARY
- Your body has an unlimited capacity for protein absorption. However, max protein synthesis maxes out at 20-40 grams of protein.
- Spread 20-40 grams of high-quality protein daily to maximize protein synthesis.
HOW MUCH PROTEIN POWDER PER DAY?
For years in the fitness industry, some have said that protein absorption is maxed at 20-30 grams of protein at a time. This has been called the protein absorption myth. Previous studies have shown that post-exercise muscle protein synthesis is maximally stimulated at 40 grams of protein independent of body weight.(1) Muscle protein synthesis is in a constant state of turnover, meaning there are increases in protein synthesis and breakdown.
HOW MUCH PROTEIN CAN YOUR BODY ABSORB IN ONE DAY?
For muscle growth to occur, muscle protein synthesis must be greater than muscle tissue breakdown. For example, protein synthesis remains negative after resistance exercise despite increased muscle protein synthesis due to protein balance remaining negative due to the increased activation of muscle tissue breakdown.(2)
Only when protein is ingested following a resistance exercise bout and protein absorption increases is there a synergistic impact on muscle protein synthesis, resulting in a positive net protein balance [6]. Furthermore, the rate of muscle protein synthesis and the rate of muscle tissue breakdown determines the net gain in muscle protein accrual.
Consumption of dietary protein or EAA stimulates muscle protein synthesis in a dose-dependent manner (i.e., 20-40 grams), however, at higher intake levels, the extent of stimulation of muscle protein synthesis plateaus.(3)
For example, in a previous meta-analysis of the literature (i.e., 49 studies with 1863 subjects) on protein and muscle hypertrophy, protein intake above 1.6 g/kg/day (.8 grams per pound of body weight) failed to increase muscle growth with resistance exercise.(4) additionally, excess protein consumption does not seem to contribute to gains in body fat. (5)
HOW MUCH PROTEIN CAN YOU ABSORB IN ONE MEAL?
Maximal muscle protein synthesis occurs at rest with 20 grams of protein, however, larger protein dosages result in greater muscle tissue breakdown suppression. For instance, when young subjects were given 40 or 70 grams of beef protein, the net anabolic response was greater for the 70 grams due to the greater reduction in muscle tissue breakdown.(6)
These findings were subsequently replicated in other studies, wherein subjects who received 70 grams of protein experienced a greater net anabolic response through reduced muscle tissue breakdown than those receiving 35 grams of protein.(7)
Consequently, although it will not further increase protein synthesis, a larger dose of protein will induce a net greater anabolic response because of greater suppression of net muscle tissue breakdown. Additionally, it should be mentioned that protein breakdown plays a minimal role in regulating muscle mass under normal caloric balance.(8)
Provided you eat sufficient calories, you will not break down muscle; protein breakdown escalates when in a deficit. Muscle tissue breakdown becomes more pertinent to maintaining muscle mass when in a caloric deficit.(9) It is widely recognized that insulin is a potent inhibitor of muscle tissue breakdown.
HOW LONG DOES PROTEIN STAY IN YOUR SYSTEM
In the past, experts advised athletes and fitness enthusiasts to consume protein and carbohydrates after exercising to maximize the insulin response. However, it is now understood that to prevent muscle tissue breakdown, only small increases in insulin are necessary, achievable by consuming 20-30 grams of whey protein. Additionally, Consuming carbohydrates beyond this will not yield any further reduction in muscle tissue breakdown.
HOW MUCH PROTEIN CAN YOUR BODY ABSORB IN ONE SITTING?
Protein absorption and the subsequent increases in high circulating amino acid levels far exceeds skeletal muscle’s capacity to utilize the amino acids for muscle anabolism.
First, the gut and liver extract ~40%–50% of the available amino acids from the ingested protein meal, primarily for the purposes of energy production and for local protein synthesis.
The remaining ~10% of the amino acids are utilized by muscles. Thus, for a 20-gram bolus of protein, roughly 2.2 grams or 11% of the amino acids are utilized by muscle for protein synthesis.(2)
In conclusion, in an excellent review article by Brad Schoenfeld and Alan Argon titled, “How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution.” They suggested that using the upper daily protein intake of 2.2 g/kg/day (i.e., 1 gram of protein per pound of body weight) reported in the literature spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal or 25 grams of protein per meal.(12)
REFERENCES
REFERENCES
7. Park S, Jang J, Choi MD, Shin Y-A, Schutzler S, Azhar G, et al. Nutrients. 2020;12(11):3276.
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