"So I got into a debate with my friend the other day. Essentially, he stated that it was stupid for me to eat more than 30 grams of protein per meal because my body could not metabolize it. Because of my constrained schedule and my dedication to intermittent fasting, I generally eat only two meals a day and fit my macros accordingly. So, is there evidence that supports his claim, or should I continue to hit my macros/micros and be fine?” -Eli
Great question. First off, let me begin by saying that that argument is one that almost everyone has had at some point and it’s understandable to be confused on the subject. Let me begin with my opinion. Considering that I am a big believer in intermittent fasting as well, I do not agree with the statement that your body can only “metabolize” 30 grams of protein in a single meal. The fact of the matter is that nearly 100% of the food you ingest will be broken down to its constituent parts in the stomach before it even hits the small intestine where those parts will be absorbed for usage. Just considering from an evolutionary standpoint. In the age of hunting and gathering, it is quite likely that hunters went for long periods of time where they did not eat. Once the time came that they had successfully hunted an animal, they presumably feasted until their hearts (or stomach’s) content. Chances are, early man likely never had heard “Hey bro, you should stop eating that buffalo, don’t you know you can only use 30 grams of protein?” If that were the case, it is quite likely that man would have never survived due to extreme protein deficiencies. Further, the same holds true for both you and I since we intermittent fast. If this claim was true, we both would likely be in an extreme state of atrophy would likely be very sick. I’m guessing this isn’t the case for you, as it isn’t for me.
If we look at what Layne Norton has to say, (one of the top current scientists dealing with science of protein), his argument is not that you won’t digest/absorb more than 30 grams of protein, but he claims that it is more of a question of how much of that protein will be used towards rebuilding muscle. You have to remember that a good majority of the rest of your body will use proteins for growth and regular function, such as organs, tissue, cartilage, etc. The real question is, how much of that protein absorbed will actually be used for building muscle? Considering that question, it intuitively would make sense to consume a higher amount of protein, in order to make sure that you are fully stimulating muscle protein synthesis after the body has used the other protein for other bodily function.
According to Layne, there is a good amount of research that actually shows that instead of the typical bro-diet of consuming smaller meals many times throughout the day, it has been shown that larger meals throughout the day (2-3 as opposed to 6-8) including larger portions of protein actually stimulate protein synthesis better. Let me break down what happens:
An interesting study that was brought to light by Alan Aragon speaks of just how good the body is at using a larger amount of protein in one meal. Store et al., 2007 showed that when two groups were assigned to consuming maintenance calorie intake in either 3 meals or 1, the group consuming all of their intake in 1 meal actually had significant changes in body composition, including a reduction of fat mass. The kicker: all subjects who completed the study “maintained their bodyweight within 2 kg of their initial weight throughout the 6 month period.” (3). That means that the group who consumed their intake in one meal got leaner, with likely minimal if any loss in lean muscle tissue. It also wasn’t stated whether or not weight training was involved. If I were to speculate, if these subjects coupled this protocol with resistance training, they would likely have lost more fat and quite possibly gained some muscle, or at least would have seen the same results as the 3 meal group, albeit with less fat.
Further, according to Alan, there is likely a cap that your body can utilize towards anabolic processes, but in his opinion it is likely closer to the amount that can be used in a single day. That being said, the current consensus is that around 1 gram/per pound of bodyweight is a good number to hit.
As for my current protocol, I find it quite difficult to hit these numbers if I save all of my food for after my workout. As such, I typically will start feeding a couple hours prior to my workout, consisting of only protein and fat. After 3-4 hours I train, and then get in the rest of my protein and carbohydrates. I have found that by doing this, I can more easily reach my macronutrient goals, but not get bogged down by carbohydrates during the day. Further, this allows me to separate my fat and carb intake, while placing all of my carbohydrates post-workout, when they will more likely be used for refilling muscle glycogen stores.
In closing, it is quite unlikely that the body can only use 30 grams of protein per meal. This whole idea really goes hand in hand with the broscience suggestion that in order to ramp up metabolism, one needs to eat many meals throughout the day (but I don’t need to tell you that’s bullshit, as a IF'er, I’m guessing you already know that). Until solid research comes out showing that bigger protein meals are inferior, or you start losing muscle by the pound daily, I’d stick to what you are doing. It shouldn't go without saying that it MAY be a better idea to split your protein intake up into a couple of meals if your goal is maximum muscle growth. I think that consuming closer to 3 meals with 50+ grams of protein every 4-6 hours would likely yield superior protein synthetic responses and thus, better muscle gains. Albeit, if due to schedule and diet, you need to consume more per meal for less meals throughout the day, the current available information says that this will likely not be a problem. Is it optimal for muscle gain to consume all of your protein in one or two meals? Probably not, but if your goal is to lose fat and minimize muscle loss, it is likely a good idea to consume more protein per meal, especially if you are intermittent fasting. But, I digress. The true reason for this article was to address the myth that the body can only use 30 grams of protein per meal, and the rest get's oxidized for energy. I think after reading this article, you'll have a better understanding of why this doesn't really hold up against the research. Hope this helps.
Also, check out the below references for more full length articles on this subject from two of the best minds in the business.
1. Aragon, A. (n.d.). Is there a limit to how much protein the body can use in a single meal? Retrieved November 5, 2014, from http://wannabebig.com/diet-and-nutrition/is-there-a-limit-to-how-much-protein-the-body-can-use-in-a-single-meal/
2. Norton, L. (n.d.). SimplyShredded.com. Retrieved November 5, 2014, from http://www.simplyshredded.com/the-truth-about-protein.html
3. Stote KS, et al. A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults. Am J Clin Nutr. 2007 Apr;85(4):981-8.