In this on-going series, Dr. Layne Norton will focus on clearing up some of most egregious B.S. that surrounds protein intake. For the better part of a decade, Layne has been researching protein metabolism as it pertains to building muscle. The emphasis of his PhD thesis was on dietary protein intake, quality and its influence on muscle metabolism and body composition. He has also put his methods into practice, getting himself and hundreds of clients into razor-sharp shape. He knows the difference between something that looks good on a PubMed abstract but that won’t work in the real world. Layne is going to use his integrated research and practical knowledge to destroy the myriad of myths that surround this misunderstood muscle-building macronutrient. Get ready.
“You can only absorb 30 grams of protein at one meal.”
Just like Lady Gaga’s wardrobe, this is wrong on many many levels.
The word “absorb” actually refers to the amount of a nutrient that makes it into circulation from the digestive tract. So if this statement were accurate, you would only absorb, say, 30g of a 50g dose of protein. So what would happen to that 20g of extra protein? Unabsorbed matter in the GI tract will pull in fluid to dilute the osmolytes resulting in rapid vacating of the bowels. Meaning, you’d s--t your brains out every time you ate more than 30g of protein. Obviously, this doesn’t happen. The truth is, most protein sources are absorbed quite well. Furthermore, if you eat a large amount of protein, your GI tract will simply slow down the digestive rate so that it can accommodate the onslaught of amino acids. You absorb darn near all of it, regardless of how much you consume.
Dainty Caveman Appetite?
The second reason this myth doesn’t make sense comes from an evolutionary standpoint. Hundreds of thousands of years ago, protein was a scarce but highly valuable commodity for humans. It was usually consumed in a massive bolus, when early man was able to bring down a meat source in a hunt and then found themselves with potentially hundreds of pounds of nutrient-dense protein. Since protein could not be preserved very long at that time, hunters would simply eat as much as they could at a sitting. It makes absolutely zero sense that our GI systems would have evolved to only absorb 30g at a time. If that were the case, our species would have gone extinct from nutritional deficiency long ago.
The Bottom Line
The root of the matter, however, is that most people who perpetuate this nonsense about “absorption” are using the word and the entire concept incorrectly. The real importance — and a fact that most mainstream talking heads are missing — is the amount of protein at a meal that will maximize anabolism. Although there is no definitive answer as to the optimal amount of protein that is beneficial at a meal, there is some research out there that points us in the right direction. Leucine is the sole amino acid responsible for triggering the anabolic response. Protein sources have shown to elicit anabolic responses in proportion to the amount of leucine they contain. It appears that consuming approximately 0.015g of leucine per pound of bodyweight at a meal will maximize your anabolic response to that protein source. So for a 200 lb bodybuilder, you would be shooting for around 3g of leucine per meal. A protein source that is rich in leucine such as whey, which is composed of about 12% leucine, would require roughly 30-35g of protein from whey to max out anabolism. For a source of protein like casein, which has a lower concentration of leucine (approximately 8%) you’d be looking at closer to 50g of protein.
If you have any protein myths or questions that you’d like me to see Layne address, drop him a line at email@example.com.