The peri-exercise period (that is; pre, intra and post exercise) is a crucial time for an athlete to promote optimal performance and recovery using dietary means. Exercise is strenuous and, depending on the duration, intensity and environment of the activity, can result in; reductions and or depletion of existing glycogen stores, increased protein oxidation, muscular breakdown, reduction in circulating electrolyte levels and reduction in hydration levels. All these associated factors, if not addressed through adequate dietary intake, can severely impede performance and recovery, if not leading to reductions in performance and recovery in subsequent bouts of exercise (be they the same day or in the days following). Therefore, the goal of dietary intake around exercise should be;
· To have a glycogen sparing effect and or restore glycogen stores
· Reduce protein catabolism
· Increase muscle protein synthesis
· Restore any loss in electrolyte levels
· Optimize hydration levels and ultimately avoid dehydration
Following exercise, nutrition plays a key role in recovery, optimizing muscular hypertrophy and adaptation as well as preparation for the next exercise session. The type, duration and intensity of exercise will influence the following, but exercise induces the following changes;
· Reduction in muscle glycogen
· Increased protein breakdown
· Increased muscle protein synthesis
It is the goal of the athlete to restore any loss in muscle glycogen, reduce protein breakdown and further elevate muscle protein synthesis. These goals can be met with consumption of a protein and carbohydrate source after training. Post-workout protein ingestion will not only further elevate muscle protein synthesis but it can also reduce protein breakdown. Post-workout carbohydrate can effectively “turn off” (if not severely reduce) protein breakdown, whilst also being used to replenish any reductions in glycogen stores.
We’re aiming for a high-quality protein source after training. This means a protein source with an adequate amount of branched chain amino acids (BCAAs). BCAAs are considered constituent members of the essential amino acid group. This means quite simply that we cannot synthesize them ourselves and must attain them from our diet. There are three BCAAs; leucine, isoleucine and valine. Leucine is the star of the show but we’ll cover its two co-stars first.
Isoleucine and valine have a range of functions, with those most relevant to exercise recovery being;
· Reduction of muscle protein breakdown
· Can be converted to glucose if necessary
· Aid in healing and repair of damaged muscular tissue
· Can stabilize and better regulate blood sugar
Onto the star of the show, Leucine. Leucine is the amino acid most responsible for directly stimulating muscle protein synthesis. It activates mTOR (Mechanistic target of rapamycin), which, long story short, is the “on” switch for muscle protein synthesis (amongst other important processes). Leucine is the main star of the show because without it, research shows that, neither isoleucine or valine intake have a significant effect on muscle growth and that, when compared to a complete mixture of BCAAs, leucine appears to be just as effect in stimulating muscle protein synthesis. Additionally, when researchers have tested a protein source without BCAA inclusion there was no effect on muscle growth. So, this is why we highlight the fact that high-quality protein sources are so, so, SO important after exercise!
Examples of high quality protein sources which can be used following training are;
· Whey protein (17.77g of BCAA per 100g – 388kcals *realistically you’d only use 1 scoop which would provide anywhere between 4 to 6g of BCAA per 30g and 100 – 120kcals)
· Egg white (2.5g of BCAA per 100g – 48kcals)
· Beef (5.4g of BCAA per 100g – 209kcals)
· Chicken (4.5g of BCAA per 100g – 165kcals)
· Cod (4.0g of BCAA per 100g – 105kcals)
For vegans and vegetarian’s high quality protein sources include;
· Tofu (7.5g of BCAA per 100g / 480kcals).
· Seeds, pumpkin and squash, roasted (7.1g of BCAA per 100g / 522kcals).
· Soybeans, roasted (6.5g of BCAA per 100g / 471kcals).
· Kidney beans, raw (4.3g of BCAA per 100g / 333kcals).
· Lima beans, raw (4.3g of BCAA per 100g / 338kcals).
· Broad beans, raw (4.2g of BCAA per 100g / 341kcals).
In terms of how much, you’re aiming to get anywhere from 25 – 40g of protein and between 5 – 10g of BCAA (inclusive within the protein source) after exercise to get the most optimal response.
Post-workout carbohydrate can have an additive effect when used in tandem with protein. You could say that carbohydrate is the Robin to protein’s Batman. On its own, post-workout carbohydrate (referring to those of higher glycaemic index scores or possibly even “sweeter” foods), thanks to its role in increasing circulating insulin levels, can further down regulate muscle protein breakdown, although administration of carbohydrate alone has no direct effect on elevating muscle protein synthesis.
Therefore, utilizing both nutrients post-workout could have the best possible outcome for further elevating muscle protein synthesis and down regulating (as much as possible) protein breakdown. In addition, it would also aid in replenishing our body’s own stores of carbohydrate (referred to as glycogen) that are utilized as fuel during exercise which can also play a role in reducing protein breakdown.
There are no strict recommendations for carbohydrate intake (given that individuals may have a certain weight-loss/gain/maintenance goal in mind), however 1 to 2g per gram of protein (or 0. 35g of carbohydrate per kg of body weight up to 1g of carbohydrate per kg of bodyweight) would be more than sufficient. For example, after training a person could have 30g of protein with 30g – 60g of carbohydrate dependent on their goals and or calorie allowance.
Carbohydrate sources can vary greatly dependent on personal preference and overall calorie intake. A few of our favourites are; cereal, bananas, frozen fruits and even (on the odd occasion) sweets. It just depends on the person, their personal preferences and their current circumstances.
Maintaining adequate hydration levels
This ties into the post-workout period but is also relevant during exercise too. As we know, when we train we sweat etc. and lose water. The goal of the athlete is to maintain hydration levels the best they can to ensure there is no negative impact on their performance.
The way in which an athlete can calculate how much water they require both during and after exercise is;
1. Weigh yourself before exercise
2. Weigh yourself after exercise
3. Calculate the difference (if any) in weight
4. Calculate how much water you consumed during exercise
5. Convert the weight from kg or pounds into grams and add this figure to the amount of water you consumed. E.g. if you lost 0.4kg this would be 400g. Add this to you given amount of consumed water (e.g. 600mls)
6. The resulting number (which in this case is exactly a litre… handy that!) is an indication of how much water you’d need to consume during the activity, as well as the amount after to ensure adequate hydration (although this may also be met from food sources).
Here’s the calculation in full;