Everyone knows you need to drink water before, during, and after exercise to replace lost fluids.  But how about what you eat and when you eat it?  The following guidelines should help athletes decide how to best fuel their bodies.

How the Body Uses Fuel During Exercise

When exercising, the body first uses blood glucose and glycogen stored in muscles for fuel.  Moderate aerobic activity can be fueled for about two hours before the body turns to fat and protein stores, so most recreational athletes do not need to worry about anything more than having enough blood glucose and glycogen.  Blood glucose can be increased with carbohydrate drinks and energy gels or bars.  Even after the first two hours of activity, when the body turns to fat stores, it needs carbohydrates to help burn the fat, so it is important to continue eating carbohydrates during the workout.

Before Exercise

One hour before exercising, eat some carbohydrates to increase glycogen and blood sugar levels.  Eating oatmeal or other cereals helps fight off fatigue and decreases hunger during exercise.  An alternative is to drink a protein/carbohydrate combination drink half an hour before working out, to help protect muscle protein from being broken down.  Also, half and hour before your workout, drink 14-20 ounces of water or a sports electrolyte drink.  This will delay dehydration, help you sweat more to cool your body, and moderate the rise in body temperature.  The time delay is important, as physical exercise immediately after a meal reduces the body’s absorption of amino acids in the intestines.

During Exercise

Drink water throughout your workout to replace water lost through sweating.  Athletes should remember that thirst is not a good indicator of hydration.  When you feel thirsty, you are already becoming dehydrated.  You should need to use the restroom every two to three hours and your urine should be clear, if you are properly hydrated. 

Water alone is sufficient for workouts lasting less than an hour.  For longer workouts, use sports drinks to replace lost electrolytes.  Electrolytes (potassium, sodium, and chloride) have specific functions, and their imbalance can be fatal.  Juices and soda also contain electrolytes, but they also contain a higher amount of sugar that can cause cramping.  During a workout, you should drink 6-12 ounces of fluids every 15-20 minutes.

Also, if it’s a long workout, consume some protein and carbohydrates during exercise, in a 4:1 carb to protein ratio.  The carbohydrates will decrease the release of cortisol, a hormone produced during intense exercise that breaks down muscle tissue.  The protein intake will keep the body from breaking down muscle to get protein for fuel. 

After Exercise

The timing of nutrient intake after exercise is important.  Nutrients consumed more than 45 minutes after exercise have much less impact in helping muscles regenerate than nutrients consumed earlier.  Consume a carbohydrate/protein combination to stop muscle breakdown and initiate rebuilding.  This rebuilding occurs by stimulating the release of insulin, which sets a cascade of events into motion that speeds muscle recovery.  It will increase the number of amino acids (protein building blocks) that can get into muscles by 50%, increase the production of protein by 2/3, and slow the breakdown of muscle proteins.  The carbohydrates will also help replenish glycogen levels.

You will also recover faster by consuming foods that have a large amount of leucine.  Leucine is found in meat, dairy, power bars, and sports drinks. It stimulates muscle protein synthesis, provides fuel for muscles, and helps maintain blood glucose after exercise. 

You should also drink 12-24 ounces of fluids within thirty minutes of your workout to continue replenishing lost fluids.

Protein

Protein has been shown to fuel activity more efficiently than carbohydrates, and it also aids in recovery after exercise.  The more protein you use for energy, the more you risk soreness as muscle fibers break down.  Cortisol is a hormone produced during strenuous exercise, and it can cause muscle fiber damage by boosting protein breakdown to fuel muscle movement.  Free radicals are also produced during exercise.  These cellular waste products lead to muscle damage and also weaken the immune system.  (This is why many high-level athletes consistently come down with nagging colds.)

A 2007 study published in the Journal of Strength and Conditioning Research showed that a drink containing protein, when compared to a carbohydrate drink placebo, consumed after exercise, helped improve anaerobic power production in athletes, but did not change strength, endurance, or body composition.  This study, therefore, shows that athletes involved in mainly anaerobic activities (sprinters, wrestlers, sprint cyclers, and swimmers) need to supplement themselves with protein post-workout.

When an athlete switches from one phase of training to another, at least two to four weeks are required to readjust energy levels and protein intake and output.  Longer adjustment are necessary if body mass is lost or gained, such as a fall football player adjusting to the winter wrestling season. 

Protein should be 12-15% of the calories consumed by athletes in hard training.  Carbohydrates should make up 55-60% of caloric intake, to reduce the chances of protein catabolism.

As there are many different types of proteins, dietary variety is the only way to increase the potential for ingesting high-quality and complementary proteins.  For the average athlete, to calculate the amount of protein you need daily, divide your weight in pounds by 2.2, and then multiply that number by .8 and 1.0.  This is the number of grams of protein you need to consume daily.  A serving (3 ounces) of meat, poultry, or fish contains about 21 grams of protein.  Half a cup of cottage cheese is 14 grams, half a cup of tofu is 10 grams, a cup of milk or yogurt is 8 grams, and an egg is 6 grams.

High-level endurance athletes need to ingest 1.2-2.2 grams of protein per kilogram of body weight, daily.  Strength athletes need to consume 1.76 grams per kilogram per day.  Most athletes get the protein levels they need without thinking about it, simply because they ingest more calories.  Protein supplementation is usually not needed.

Supplementation

Just as nutritional supplements are becoming more popular for wellness, there are supplements that will specifically aid athletes.  Digestive enzymes will optimize the nutritional benefits derived from foods and other supplements.  Glucosamine and MSM are useful for maintaining joint integrity.  Boswellia, essential fatty acids, ginger, and turmeric all help control the inflammation associated with the wear and tear of exercise.  Coenzyme Q10 and carnitine aid endurance and help athletes avoid “hitting the wall.”  Electrolyte replacement will lead to less soreness and cramping.  Vitamins B1, B2, and niacin are all needed by the body in direct proportion to the intensity of exercise, so adjust your B-complex vitamin accordingly.  A broad-based multivitamin/multimineral supplement containing nutrients at about 100% of the Recommended Daily Allowance will lower the potential for reduced vitamin and mineral status.

For specific sports, Vitamins A and B1 are generally deficient in football players and wrestlers.  Wrestlers are also usually low in potassium.  Distance runners generally are low in iron.

Conclusion

Keep a logbook of food and fluid intake with your exercise log to track your sports nutrition progress.  Take notes on how your workout feels and look back and see how you ate and drank that day.  You will start to notice your own trends and realize that healthier eating habits will make your workouts feel better, and your competitions much more effective!

References:

Baechle, Thomas R., ed.  Essentials of Strength Training and Conditioning.  National Strength and Conditioning Association, 1994.

Beck, Travis W., et. Al.  “Effects of a Drink Containing Creatine, Amino Acids, and Protein Combined With Ten Weeks of Resistance Training on Body Composition, Strength, and Anaerobic Performance.”  Journal of Strength and Conditioning Research 21(1) (2007): 100-104.

“Boosting Fitness:  Recovery Phase.”  Energy Times Mar 2003:  70.

Dewon, Joyce.  “Summer Sports Nutrition Guide.”  Energy Times Jul/Aug 2004:  26-31.

“Maximizing Your Muscle:  How Much Protein Do You Really Need?”  Aurora Healthcare Healthy Diet Newsletter Oct 2004.

“Sports Nutritionals.”  Chiropractic Economics Sept 2006:  35-40.

VanErmen, Christina, RD, CD.  “Running on Empty.”  Aurora Healthcare Sports Page Nov 2004.