The Truth About Post Workout Nutrition

Don’t get stuck in a pattern of doing something because you’ve always done it that way. Question and research your beliefs regularly. I would religiously drink my post workout shake after every workout, making sure I would be sipping my protein during my cool down stretching. It’s funny how marketing tactics can become so engrained in our beliefs & actions that we simply don’t question it.

This post serves to shed some light on the actual science surrounding post workout nutrition. Just like most dogmatic practices, it pays to do some research. What’s most surprising about my research is the fact that there is little to no evidence to support the quintessential consumption of a post workout shake high in carbohydrates & proteins.

Refueling glycogen & protein supplies

There is a study that shows combining simple carbohydrates & protein within a two hour window ‘significantly greater glycogen resynthesis compared to ingesting a calorie-equated carbohydrate solution alone’, however this was for subjects who cycled for 1-2 hours. There are no studies that robustly show positive effects for those participating in strength sports.

Regarding strength based exercise (which constitutes 6-9 sets of exercises for a given muscle, glycogen stores in the body are only depleted by about 36-39%. So the urgency in consuming carbohydrates immediately after strength training is blunted.

One study looked at bodybuilders and compared an immediate post-exercise consumption of a series of high glycemic meals with a two hour wait post-exercise and found no difference in glycemic levels in the body after an eight & 24 hour post-exercise period. Another study, replicated this and added 165g of fats to the post exercise meals (to blunted any high glycemic effect) and found to effects on the blood glucose levels either.

Other studies that link post exercise consumption of protein with positive outcomes, didn’t account for the extra intake of protein. That is to say, those ingesting a post exercise shake, had a higher daily intake of protein than those in the control group. This doesn’t provide evidence for the post workout shake, rather shows that a higher intake of protein is beneficial to hypertrophy. The setup of the study makes it impossible to show causation between post workout protein consumption and increased hypertrophy.

The post exercise window of opportunity is the secret to boosting anabolism

The claim is that there is an increase in Muscle Protein Synthesis right after strength training, meaning one should consume a shake consisting of highly digestible carbs & proteins in order to take advantage of this in order to build muscle faster. There is no data or study that is able to prove the existence of a post exercise anabolic window and the studies that do exist cannot come to common ground regarding any optimal timing for post workout nutrition. Abiding by the common consensus of 1.1-1.25g/lb of body weight of daily protein intake seems to be the better strategy for long term muscle growth.

Here is a great table summarizing the studies looking at muscle protein synthesis

The studies that find ‘beneficial’ effects from immediate post exercise consumption of carbs & proteins, were from those subjects that were in a fasted state, or hadn’t eaten for 4-6 hours prior to exercise.

For those that had a pre-workout shake consisting of carbs & proteins, there was no beneficial effect from having a post workout shake of carbs & proteins.

Studies show that there is an elevated rate of muscle protein synthesis after strength training (that seems obvious), what is not as well known is how long this last for. For those that are untrained, the ‘post workout window’ lasts for 24-48 hours, whereas trained individuals experienced 12-16 hours.

Reduce soreness & increase recovery

There is still no scientific understanding of what exactly causes Delayed Onset Muscle Soreness (DOMS), subsequently there are no proven methods to reduce or prevent DOMS. The only thing that we can safely say is that DOMS seems to be prevalent due to novel stimulus. It is neither a sign of an effective workout, nor is lack of DOMS a sign of an ineffective workout.

This might be helpful with athletes who are performing multiple times in one day (e.g., Powerlifters, Crossfitters, Strongmen, Olympians on their day of competition). But this is more an issue of consumption of enough calories before the next event rather than taking advantage of some post-exercise window of anabolism.

For those that aren’t in a highly competitive field or aren’t training multiple times a day. The timing of nutrition comes back to the regularly spaced meals, 3-6 meals spaced apart by 3-5 hours.

Take Home

  • Don’t pay attention to the ‘post workout anabolic window’, scientifically it doesn’t exist.
  • Your daily intake of calories, carbohydrates, proteins & fats is what you should be concerned about. If you aim to eat every 3-5 hours, then your body will be in an optimal state to partition nutrients over the course of a day.
  • Muscle Protein Synthesis is elevated for 16-48 hours post exercise, (depending on if you’re a beginner or advanced trainee) and is most efficient when protein is split evenly across a day.
  • If you train in a fasted state, then a post workout meal/shake is more important simply for the purposes of refueling the body.
  • Daily protein intake should be in the 1.1-1.25g/lb of body weight and split evenly across 3-6 meals at a rate of 0.3-0.4g/lb for each meal.
  • Without proper tracking/intake of macro nutrients, then timing doesn’t matter.
  • When considering timing of nutrients, consider shifting to higher carbohydrate, lower fat meals around workout times.

References:

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