Early research into post-workout nutrition focused almost exclusively on endurance athletes and, really, the only issue of importance was refilling muscle glycogen and re-hydrating the athlete. For this reason the focus was on carbohydrates and fluids with little else considered. At some point, I recall it being the mid-90’s some early work suggested that adding protein to post-workout carbohydrates was beneficial in terms of glycogen re-synthesis and a new dietary trend started to form.
Now, it turns out to be a bit more complicated than that whether additional protein actually increases glycogen synthesis depends on a host of factors, primarily how much carbohydrate is provided. Simply, if sufficient carbohydrate is given following training, adding protein has no further benefit in terms of promoting glycogen re-synthesis.
In situations where insufficient carbs are consumed (by choice or otherwise), extra protein helps. Which isn’t to say that additional protein following training isn’t valuable for endurance athletes even if carbohydrate are sufficient but that’s not really the topic of today’s article.
While individuals involved in the strength sports and bodybuilding were quick to jump onto the post-workout carb/protein bandwagon, the research wasn’t really aimed at them. As well, there has always been a bit of a disconnect in using work on endurance athletes (who may be doing hours of exhaustive work) and trying to apply it to individuals in the weight room.
Differences in volume of training, fuel use and goals make using data on one group inappropriate for application to the others. It’s still common to see well-meaning nutritionists use the same guidelines for both strength/power athletes (including bodybuilders) and endurance athletes but that is simply silly.
In any case, work examining the impact of various combinations of post-workout nutrients in terms of promoting strength or hypertrophy would come later and, at this point, a huge amount of work has been done. I’m not going to get into every detail (the issue is discussed in absurd detail, 35 pages worth, in The Protein Book) of post-workout nutrition and will focus the article simply on the issue of protein, carbohydrates and the combination of the two in terms of how they impact on post-workout recovery and muscle growth.
To understand what I’m going to say and why I think some current recommendations (especially the one saying that you only need protein post-workout) are not consistent with the research, I need to get into a few details regarding how training impacts on muscle growth and how nutrients impact on this. Don’t worry about the dense text, there’s a pretty graphic below to help explain it all. A pretty, pretty graphic.
After an intense weight lifting workout your body system is characterized by three main factors:
1. Glycogen Stores are low.
2. Protein Breakdown is increased.
3. Muscle Protein Balance is negative.
Therefore, for a rapid recovery from exercise, immediately after a workout (strength or endurance), you must:
1. Rapidly replenish the low glycogen stores in your muscles.
2. Rapidly decrease the muscle protein breakdown that occurs with exercise, especially high intensity bodybuilding training.
3. Rapidly force further increases in muscle protein synthesis in weight trainers and/or restore muscle-protein synthesis in endurance athletes.
Failure to accomplish any one of these objectives will lead to a lowered rate of recovery from your workout. And the slower the recovery process is, the less muscle growth you can stimulate!
Studies have found that delaying nutrients (protein and carbohydrate) consumption after a workout can greatly reduce the rate of glycogen restoration and protein synthesis. In fact, the rate of glycogen synthesis is reduced by 50% if nutrients are not consumed immediately after a workout. Besides, delaying post-workout nutrients absorption will negatively affect protein synthesis.
A few hours after a workout, the insulin sensitisation stimulated by intense training will be much lower: there is a two to threefold increase in insulin sensitivity immediately post-workout. After two or three hours, it is down to only 44% above baseline (Levenhagen et al. 2001). So basically, if you wait too long after your workout to consume a mix of fast absorbing proteins and high glycemic carbohydrates, the amount of muscle you will build in response to your session will be significantly decreased.
There are two key factors to rapidly increasing post-workout glycogen synthesis:
1. Adequate carbohydrate availability (to convert to muscle glycogen).
2. High insulin levels (to stimulate glycogen storage and shuttle carbohydrates into the muscle).
An ideal post-workout muscle growth stimulating formula would include fast absorbing proteins, high glycemic carbohydrates, and some additional BCAAs (which have been shown to drastically increase protein synthesis and decrease protein breakdown on their own). Certain amino acids can increase the insulin response to meals. By adding certain amino acids to the carbohydrate/protein beverage in the above study, the insulin responses were considerably higher than the carbohydrate/protein beverage alone.
In order to maximize these two key factors you need to increase the gastric emptiness rate as much as possible. The different proposed ingredients must be fast absorbing. To achieve this goal you must dilute these nutrients into a lot water quantity. Liquid nutrition is more rapidly digested and absorbed, nutrients are more rapidly delivered to the muscle.
The final piece of the post-workout puzzle is the management of protein synthesis. And although this area is a little more complex than managing protein breakdown, there are three key ingredients to increasing protein synthesis immediately after workouts:
1. A proper ratio of BCAAs.
2. High blood levels of essential amino acids.
3. High blood levels of insulin.
You must prioritize 3 main factors as soon as possible.