Eating for Sports
Written by Dr. L. Lee Coyne.
When it comes to nutritional advice for sport and exercise there is always some new "magic bullet" product or plan designed to help you become the next super athlete. This is not a new phenomena. Man has altered diets to enhance performance since ancient times.
Many years ago my Classics professor related the fact that the gladiators were reported to have eaten ground lion's teeth and raw meat prior to a performance in an attempt to take on the ferocious characteristics of the lion and therefore improve their chances of success.
An examination of a few nutritional practices and procedures associated with intended performance improvements seems warranted.
The first consideration of every athlete should be to eat as healthy as possible to ensure a strong immune system and thus prevent illness. One of the major contributors to ill health is "free-radical" damage to cells. Such damage can be the underlying cause of many forms of cancer, heart disease and other cellular damage.
It is well established that among marathon finishers, 40% experience some form of illness within one week of completing their race - a sign of a depressed immune system.
Free radical production is a natural occurrence during intense exercise. To prevent free radical damage one needs to eat more free radical scavengers known as "anti-oxidants" (beta carotene, other carotenoids, Vitamins C & E, selenium, lycopene, etc.) obtained from fresh fruit, vegetables and supplements.
Optimum health is also dependent upon eating adequate high quality protein to produce those immune cells and obtaining enough "essential fatty acids" (EFA's) to produce the super hormones which control all other hormones.
Many nutrition coaches are now recognizing higher protein requirements for athletes. Endurance athletes may need more protein than body builders because they tend to "challenge" their bodies at high intensities longer.
Recent studies published in the American Journal of Clinical Nutrition reported that women who ate 24% or more of their calories from protein experienced significantly fewer heart and cardiovascular problems. Also, in a recent issue of the journal "Cancer" it was reported that women on higher protein diets experienced better breast cancer survival rates. In the same study, contrary to many previous reports, fat intake, including saturated fat, had no bearing on the results.
A study from the University of Buffalo has shown suppressed immune systems during very low fat diets. The American Heart Association has declared that fat intakes below 30% of calories "are unfounded and potentially dangerous".
Then there are innumerable studies showing the positive role of essential fatty acids (from nuts, seeds, cold pressed oils and supplements) in the prevention of heart disease, cancer and inflammatory conditions. Very low fat diets do not contain enough EFA's.
Carbohydrate (CHO) loading and pre-event hydration have been the trend over the last 15 years in the sports nutrition literature.
Carbohydrate loading has been over-done and that can account for the difficulty some have in losing weight or in controlling their cholesterol, or triglycerides or blood pressure or PMS to name a few problems. The role of CHO loading is to delay muscle glycogen depletion. Such depletion can be the limiting factor in successful completion of intense, long duration tasks. However such depletion does not occur unless one performs at a very high percentage of capacity (75%+ for over 90 minutes). This intensity is rare even for competitive marathoners.
Yes - one can deplete glycogen during an intense marathon or triathlon but not during a sub one hour, sub-maximal work out. Most training sessions occur at an intensity of 50 to 65% of capacity. During such intensities 35 to 60% of energy expenditure is still coming from fat.
Recent published studies from Denmark, Japan, New Zealand, England and the University of Buffalo have demonstrated success with a concept of "Fat Loading". Apparently there is adaptation to fat burning and it is as effective as CHO loading with the added advantage of not over stimulating insulin production, which can set up immune challenges and inflammatory conditions.
I personally have completed six Marathons without CHO loading and following a 40 - 30 - 30 diet plan throughout training.
There may still be rationale for using a high quality sport drink (one made of glucose polymers like maltodextrin and not table sugar – sucrose - plus a good level of at least 6 electrolytes not just sodium and potassium) during and after long intense runs. Sub one hour, sub maximal work-outs do not implicate the use of more than water unless the environment is very hot.
Once intense exercise is completed, recovery of spent glycogen and replacement of metabolized "Branched Chain Amino Acids" (leucine, iso-leucine and valine) becomes the focus.
Research from the University of Texas published in the early 90's, verified by others since, reported that drinking a carbohydrate (glucose polymer) mixed with a protein containing a high BCAA profile (whey protein isolate), in a ratio 3:1 in favor of CHO, provides optimum glycogen recovery and enhances muscle recovery. It reduces muscle soreness and reduces any feeling of "heavy legs" following exercise.
Depending on how long and intense the workout - some re-hydration with the high quality sport drink may be implicated following exercise.
To feel your best, stay healthy, perform best and recover fast follow some of these guidelines.
- Eat high "nutrient dense" fruits and vegetables to obtain antioxidants
- Eat high quality protein, approximately 1 gram/pound of desirable weight/day to help build healthy immune cells. Eat 20 - 30 grams of protein in the hour before training or competing. Never eat more than 35 grams of protein in a single meal.
- Eat high quality nuts, seeds, cold - pressed oils as sources of EFAs.
- Supplement with Soy Protein isolate drinks, EFAs (lecithin, EPA, GLA, Flax seed oil) and antioxidants.
- Use a high quality sport drink during and after long, intense, hot environment runs.
- Recovery Drinks (3:1 in favor of CHO) have shown excellent results