Athletes and Protein: Are You Getting the Most Out of Your Diet?
No limit to protein absorption post-workout?
What does this mean for athletes?
Before we talk about the study this blog is referring to, I want to make it clear that when talking about protein and absorption, you absorb nearly all the protein you eat. The real question is whether or not all of the protein eaten and absorbed is used for anabolism (building muscle).
A recent study has the health and fitness industry questioning whether there is an upper limit to protein intake, particularly post-workout. In this study, untrained individuals, all male, underwent a demanding resistance training workout and were then given either 0, 25, or 100 grams of milk protein isolate (MPI). For the 12 hours following their workout, they were assessed for muscle protein synthesis (MPS), amino acids present in plasma, and other markers of anabolism/muscle growth.
The study showed that 100 grams of protein produced significantly more muscle protein synthesis than 25 grams of protein. This seemingly contradicts existing data demonstrating an anabolic cap of about 20-30g protein post-workout or at a meal. It is also in contrast to recommendations that post-workout protein intake should be between 0.25-0.3 g/kg, which, depending on the athlete’s weight, can be quite a large range.
So why do some studies show an anabolic cap to a meal and others don’t? The major difference is this particular study assessed the MPS response after a fasted, demanding resistance training session in untrained subjects. The protein turnover response in untrained subjects is massive when compared to trained and elite athletes, and also creates a huge demand for tissue repair and remodeling. This allows for greater usage of amino acids from food. Additionally, the protein source, MPI, is 80% casein which does not create the same anabolic response as other protein sources, like whey.
I think this study is interesting and fills a gap in the research, but way more data is needed in this particular area to change current recommendations for protein intake for athletes. I’d be curious to see what a similar study would find in trained and/or elite-level athletes. For now, my recommendations remain the same: space protein out evenly throughout the day over meals and snacks, aiming for 20-40 grams of protein at meals, and replenish protein post-workout by incorporating 0.25-0.3g/kg of protein in a snack or shake afterward. If you’re having trouble understanding or calculating your protein needs, reach out to our Registered Dietitian by clicking here.
Access the full study here.
-Claire Igoe MS, RD
