Fuel Your Engine - nutritional intake during exercise

American Fitness, July, 2000 by Nancy Clark

Common misconceptions regarding proper nutritional intake can reduce athletic performance efficiency.

As a sports nutritionist, I commonly listen to active people describe their (sub-optimal) fueling patterns. I frequently hear comments like, "Something must be wrong with my diet. I'm just not getting what I want out of my exercise program!"

The following highlights common fueling blunders that weaken the workouts of novice exercisers and elite athletes alike. Hopefully, it will deter you from making the same mistakes.

Error #1. "I exercise on an empty stomach."

Somewhere in sports nutrition history, the idea that pre-exercise food sits in the stomach and hinders athletic performance was born. To this day, numerous casual exercisers and competitive athletes alike go to great efforts to avoid food for at least three or four hours before exercise. By doing so, they miss out on the performance benefits associated with being well-fueled. The "put gas in your car first, then go" theory that works so well for automobiles also works well for active people. You'll have far greater stamina and endurance when you run on fuel, not fumes. The following study confirms this point.

On two occasions, seven cyclists exercised to exhaustion, maintaining a moderately hard pace (70 percent VO2 max). In one trial, they ate a 400-calorie meal (breakfast) three hours before exercising. In the second trial, they simply had dinner the night before, but no breakfast. When they exercised "on empty," they bicycled for only 109 minutes, compared to the 136 minutes completed by the group who ate breakfast. That's almost half an hour longer! Exercising "on empty" left them lagging. [Med Sci Sports Exerc 31(3):464, 1999]

Error #2. "I don't bother to drink anything during exercise if I'll be working out for an hour or less."

Whether you're going for a one-hour run, using the StairMaster for 45 minutes or skating hard during the 50 minutes of allotted ice-time, you may be tempted to "not bother" bringing a water bottle or sports drink. After all, you're unlikely to get dehydrated in that short amount of time ... right?

Think again. Despite popular belief, what you drink during a short intense workout or competitive event (1 hour or less) does have a significant effect upon performance. Here's what the latest research shows:

On three occasions, athletes were asked to complete an exercise test designed to simulate a 25-mile bicycling race. They bicycled hard for 50 minutes (80 percent VO2 max) and then completed a 10-minute sprint-to-the-finish, during which they worked as hard as they could. When the athletes drank more water (48 oz., the amount needed to offset dehydration), they sprinted 6 percent faster compared to the baseline trial, during which they drank only 7 oz. of water in the initial 50 minutes of riding. When athletes ingested 300 calories of a sports drink during the first 50 minutes of riding, they improved 12 percent over the baseline trial during the sprint. [Med Sci Sports Exer 27:200, '95]

For an ordinary athlete or an Olympic hopeful, this study means that consuming an easily digested combination of water and carbs (such as a sports drink or water plus hard candies, defrizzed cola, figs, gel, etc.) will help you exercise harder and better at the end of one hour. Wouldn't you want to be 12 percent better than your poorly fueled opponent when the event is down to the wire?

Error #3. "I know I'd be a better athlete if I could just lose these last few pounds."

Runners, cyclists, skaters and soccer players--as well as many female athletes and myriads of health club members--sincerely believe they'll be able to exercise better if they could shed some body fat. Yes, trimming excess flab does lighten the load, and having less to lug around can help you exercise better. However, starving yourself to shed the few pounds that resist leaving your thighs or abdomen will not transform you into an Olympian! The cost of dieting to a "perfect" weight is often greater than any benefits gained by being lighter. Skimping on calories to lose body fat simultaneously results in skimping on protein your muscles need for growth and repair and vitamins and minerals to help fuel your body.

Athletic performance improves only when you exercise longer or harder. When dieting, you are unlikely to exercise neither longer nor harder. Also, if you have to severely cut calories in order to see any weight loss, keeping those resistant pounds off will be very difficult once you do manage to lose them.

Weight management is more than a matter of willpower. If you are far leaner than other members of your genetic family, think again about trying to be the "perfect" weight. If you are already lean but still want to be leaner, pay more attention to improving performance through optimal fueling and training. Trust that appropriate eating plus appropriate exercise will pave the way to an appropriate weight for your body.

No literary proof exists supporting the notion of the leanest athlete being the best athlete. You just can't expect to train or compete at your best if you are dieting too hard and have poorly fueled muscles. Athletes perform better when well-fed!