Despite the prevailing myth, you can and should eat more than
30 grams of protein per sitting. But exactly how much?
Protein absorption. As long as I can remember, people in the fitness biz have believed that
you could only absorb 30 grams of protein in one sitting. No one ever bothered to explain
what will happen if you ate 31 grams, but the thinking must be that the small intestine will
act as a power forward in the NBA and reject that shit, its thousands of villi shaking like so
many fingers to say, “Not in our house.”
They considered this 30-gram barrier an immutable fact, and no one knows for sure where
it originated, but we can safely say it’s wrong. The only limits to the amount of protein you
can absorb in one sitting is the size of your stomach.
Protein Synthesis: Only Part of the Equation
Things make more sense when you examine the different ways your body uses protein. If you
ingest 30 grams of protein after a workout, muscle protein synthesis will increase by
about 50%, but that’s where it gets stuck.
You could triple your protein intake to 90 grams in that one sitting, but muscle protein synthesis (1)
will not increase. That might not be true for steroid users, but we’re talking about people who
have a neck.
That’s not proof that the 30-gram-per-sitting people were right. They forget that protein is used
for a number other stuff. The body gives priority to that other stuff.
Protein, as you know, is an essential nutrient. It’s broken down into amino acids and the body
can’t get them from fat or carbs, no matter how tasty they are. We use these amino acids to
make hormones, enzymes, immune factors, and other non-muscle tissues. Once we meet the
protein requirements for all that stuff, the body can use the surplus to increase muscle protein synthesis.
In other words, you can’t rob Peter’s hormone and enzyme requirements to pay Paul’s muscle
protein synthesis wants. In APCO police code, that qualifies as a 10-65, or Armed Robbery–don’t
confuse it with a 10-68, Livestock in Roadway.
Protein Absorption – So How Much Per Sitting?
Looking at the information above, it makes sense for most lifters to take in around 40 grams of
protein in one sitting. This should be enough to fulfill the hormone, enzyme, immune factors,
and non-muscle tissue requirements, besides providing enough protein to maximize muscle
Of course, human beings vary in size, activity levels, age, and hormone levels, but the 40 grams
per serving number is a good number for most people, most of the time. In fact, T-Nation
contributors Brad Schoenfeld and Alan Aragon came up with similar recommendations in their
landmark study of the topic (2).
Is Eating More a Waste of Time and Money?
That brings us to the next logical question: What happens to any protein intake beyond 40 grams? Quite simply, it gets turned into glucose and is either used for energy or stored as fat. However, there are good reasons why you would want to use protein as a source of energy instead of carbs or fat:
- Protein keeps you full longer, thus putting the kibosh on the urge to eat surplus calories.
- Protein has the largest TEF (Thermic Effect of Food) of the three nutrients (fat, carbohydrate, and protein). If you eat 100 calories of protein, it takes 10 of those calories to process it.
- Protein has a minimal effect on blood sugar levels, so there’s no surge of insulin.
So, for purely muscle building purposes, take in around 40 grams per serving. For body composition purposes (the largest amount of muscle, the least amount of fat), take in more than 40 grams per sitting, up to 35 to 40% of total calories.
- Symons TB1, Sheffield-Moore M, Wolfe RR, Paddon-Jones D. “A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects,” J Am Diet Assoc., 2009, Sep (9); 1582-6.
- Brad Jon Schoenfeld and Alan Albert Aragon, “How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution,” International Journal of Sports Nutrition, 2018, 15:10.