Nutrition before and after exercise

I've had a number of questions from coaches after the Swim Ontario Conference last month on what swimmers should be eating after practice. The single most important rule of great sport nutrition is to develop a great diet based on balanced food sources which follows basic principles of healthy eating.

The best system I've ever come across for great nutrition recommendations for people to follow, either while involved in sports or to stay as healthy as possible is Dr. John Berardi's Precision Nutrition system. It sets out the 10 basic rules to follow for healthy eating, has CD's and DVD's to explain things in detail, and a customization guide to help build your own program. His books and online community can be accessed at www.precisionnutrition.com.

During workout you might try something like the C2max from Powerbar.

After exercise we are looking for a 4:1 ratio of carbs to protein, and if you need something quick you can try recovery products from Powerbar or EnduroxR4.

If you need a protein powder we recommend Living Protein, and if you need a comprehensive supplement that has every vitamin and mineral you will need to stay healthy and to recover from training we only recommend Living Fuel. It's not cheap, but it is the best, and you don't need any other vitamin or mineral supplements. It has also been tested free of banned substances for athletes.

We also recommend that athletes, especially girls and women, try to increase their iron intake.

Here are some specific recommendations for exercise developed by R.D. Denis Colier (that you can download by clicking here).

Pre-Exercise Nutrition

In general, the functions of a pre-exercise snack are as follows:

1. Prevent low blood sugar  by optimizing muscle and liver glycogen stores
2. Ensure proper hydration
3. Leave the athlete neither hungry nor with undigested food in the stomach
4. Provide positive psychological reinforcement that the body is well fueled
5. Avoid the exaggerated increase in plasma insulin concentrations that sometimes results in rebound hy-poglycemia in susceptible individuals.

The characteristics of high performance pre-exercise foods.
High in carbohydrate to maximize glycogen stores
Low in fat and fibre to facilitate gastric emptying and minimize gastrointestinal distress
Moderate in protein
Familiar and well tolerated, as determined through experimentation in previous sessions

3-4 hours before
The general rule is that 3-4 hours are needed for a large meal to digest (obviously, the smaller the meal, the quicker it can be digested). Most (but not all) studies have shown that ingestion of a meal containing 140-330 grams of carbohydrate 3-4 hours be-fore exercise has enhanced performance. Defining the best amount of pre-exercise food for an individual is difficult because tolerances vary greatly from person to person. Also, the amount of carbohydrate consumed in the pre-exercise meal should be weighed against the total daily amount of Calories required by the individual i.e. someone with a greater energy requirement would choose an amount of pre-exercise carbohydrate at the upper end of this range. The most likely mechanism for the improvement in performance is maintenance of blood glucose levels during exercise via increased muscle and liver glycogen.

60 minutes before
Individual practice should be based on individual experience, but small snacks that are mostly carbohydrate are probably best.  Try to figure out what works best for you. Although it is not necessary to eat during the hour before exercise, neither is it likely to be harmful to performance as was once speculated. If you must eat during this time period (for exam-ple, trying to squeeze in a snack before a morning workout) choose a smaller meal of easily digested foods.

Eating before morning workout
Liver glycogen is largely the source used to maintain normal blood glu-cose levels. However, these stores are labile and may become substantially depleted over the night. Beginning a workout with low blood sugar is likely to lead to early fatigue. Herein lays the importance of eating before morning events.
As stated in the previous sections, 3-4 hours may be needed to digest a large carbohydrate meal. If the exercise session is early enough to make wak-ing up 3-4 hours before impractical, a smaller carbohydrate snack can be consumed 30-90 minutes before ex-ercise. It is suitable for the snack to be 200-400 Calories, with the higher end of the range being more appropriate for consumption with more time before the exercise. Additionally, if the individual knows they are likely to eat little or nothing before morning exercise, having a quality high carbo-hydrate dinner or snack the night be-fore can compensate somewhat.

The most important nutrient - WATER!!!
The fact that water is vital for peak bodily function is unequivocal. Although a separate paper could be written on the benefits of proper hydration and the dangers associated with dehydration, some general guidelines for pre-exercise fluid consumption will now be discussed.
The day before an event, drink an extra 4-8 glasses of fluid so that you over-hydrate. Such a practice is tolerated well by most people. Up to two hours before the start of an exercise approximately 500 mL of fluid should be consumed. Drink another 250 mL 30 minutes before, then another 250 mL 15 minutes before the exercise begins.

Post-Exercise Nutrition

Proper nutrition is a significant factor in achieving your goals. The contribution to such goals made by nutrition in the period immediately following exercise are absolutely critical. Three important concepts need to be considered when examining any diet plan: Timing (i.e. when) 2) Nutrient quality (i.e. what kind) 3) Nutrient quantity (i.e. how much).

Carbohydrates
Carbohydrate is the predominant source of energy for muscle metabolism during short (<60 sec) bouts of supra-maximal work and the preferred fuel for muscle for prolonged, moderate intensity exercise lasting up to 4 hours. Several studies have shown that resistance exercise depletes muscle glycogen. Early carbohydrate consumption after exercise is of par-ticular importance when the recovery time before the next exercise session is short (4-8 hours), but full glycogen re-synthesis can occur with appropriate eating within 24 hours, regardless of the timing of carbohydrate ingestion.

Protein
There is data supporting the theory that protein/amino acids contribute very little as an exercise fuel. However skeletal muscle contains about 50% of total body protein and resistance exercise substantially elevates protein turnover. Also, it has been proposed that endurance exercise can induce muscle protein damage, especially when the exercise has a large eccentric component. Consumption of a snack containing both protein and carbohydrate after exercise is the strategy all active individuals should follow. This may lead to increased muscle protein synthesis and faster glycogen re-synthesis.
 
Summary
In summary, carbohydrate (in the form of glycogen) and protein (in the form of skeletal muscle) will be depleted during exercise (be it resistance or endurance training). The meal should have carbohydrate (to ensure your glycogen stores are topped up and ready to supply you with the energy you`ll need for the next workout) as well as protein (to promote the building of lean muscle tissue). Some examples of snacks that fit this criteria are:
Turkey sandwich on whole wheat bread with 2 tablespoons of low fat mayonnaise and an apple (61 grams carbohydrate; 17 grams protein)
1 cup of trail mix (71 grams carbohydrate; 22 grams protein)
375 mL of 1% chocolate milk and a banana (67 grams carbohydrate; 13 grams protein)
Geni-Soy bar and 1 cup of Gatorade (49 grams carbohydrate; 14 grams protein)