I wan’t to poke my eye out with a fork every single time I hear this BS. “You can only digest 30 grams of protein at a sitting!” Perhaps you have heard this crap too “All that extra protein is a waste and just ruins your kidneys!” If I had a nickel for every time some overweight person said this to me, I would be sitting on a beach somewhere, not writing this article for Mind and Muscle. To poke holes in a fallacy of epic proportions, you need to first find the genesis of this silly rumor. What study did somebody extrapolate data from to bastardize to their own liking? Once you look at the study, it will generally lead you to the conclusion that someone doesn’t know how to read a study. I read over the abstract of the study that lead to this conundrum regarding protein intake. I will say it now and I will say it again “TO THINK THAT THERE IS SOME ABSOLUTE LIMIT ON HOW MUCH PROTEIN A BODY CAN ABSORB IS SHEER IDIOCY! There, I screamed it for all to read.
I could shoot this entire myth down simply in one sentence and most would know it is true. Do you really think my 250 lb body with 10% bodyfat will absorb the same protein as my 50 lbs 6 year old daughter? Does that even make one shred of sense? No, because this supposed 30 gram mythical barrier doesn’t exist. If you hold to an evolutionary process in human beings, than how does that make any sense. If you eat more than 30 grams of protein, it just takes longer to digest which just slows down absorption rates. This fallacy was started after a 1997 study by Boirie and his colleagues (http://www.ncbi.nlm.nih.gov/pubmed/9405716). They tested both casein and whey protein. They found casein digested slower and whey was much faster; nothing earth shattering there. 30 grams of whey was absorbed in 3-4 hours time, they believed that on 30 grams could be absorbed in one sitting. If you eat 6 meals per day, then 30 grams is the max you can eat right? Wrong!!!
The breakdown of the study was theorized incorrectly. The first issue was they looked at whey absorption in a fasted state. It stands to reason that if it took 3-4 hours to absorb 30 grams on an empty stomach, it would take much longer if food was already in the stomach. The data suggests that whey protein digests at 10 g/hour and casein was still being digested at 7 hours at the cessation of the experiment. It makes sense that if other macro-nutrients were in the stomach i.e. fat and carbs, it would slow the rate even more. So what does this mean? It means that regardless of whether you ate 50 grams of protein or 70 grams of protein, it ill be digested until it is all broken down. Kapish! So if you ate 100 grams all day, it will take the time it takes to digest all 100 grams and the same holds true if it were 500 grams. The difference, the time it takes to completely digest both amounts. There is no magical barrier. There, got that off my chest!