Timing is everything: if you think the fastest way to a lean body is to eat less and work out more, read on and learn about the surprising new research

Muscle & Fitness/Hers, August, 2004 by Martica Heaner

WHEN THE TORCH IS LIT IN Athens this summer, lots of athletes will be watching the clock--and not just because they don't want to miss their events. New research showing that when you eat is just as important as what you eat has resulted in several elite athletes changing their eating habits. By concentrating on timing their meals and snacks just right, many of them have now been able to report being leaner, less fatigued and more focused. "We've found that athletes who match their food intake to their energy expenditure at any given hour not only are less likely to 'bonk,' they are more mentally alert and have better muscle-to-fat composition than athletes who eat erratically," confirms Dan Benardot, PhD, RD, one of a group of nutritionists and exercise physiologists at Georgia State University (Atlanta) at the forefront of studying the effects of meal timing on athletic performance.

While the athletic diet has been analyzed to death, looking at the timing of eating is new--and it's changing the way competitors eat, as well as how active, recreational exercisers eat. Here's what you need to know to develop your own optimal eating schedule.

I LEARN THE NEW ENERGY EQUATION

Common wisdom has it that if the amount of calories you consume equals the amount of calories you burn, you'll stay in energy balance, and neither gain nor lose weight. That's been the assumption, anyway. But Benardot and his colleagues' research essentially throws that traditional energy equation out the window. The researchers found that when and how often their athletes took in calories throughout the day made a big difference in each person's day-end energy balance.

One study, for instance, showed that female gymnasts and runners who didn't eat or snack for three hours or longer had the highest body fat percentages--even if they weren't consuming more calories than they were burning. Furthermore, the longer the gap between eating times, the higher the body fat, especially if they exercised during those noneating periods. Keep in mind that these were competitive athletes training hours every day--they weren't overweight. But when compared to fellow runners and gymnasts, those who ate fewer and bigger meals retained higher levels of body fat.

Perhaps even more surprising, the same study showed that those who ate less than their energy needs--traditionally the recipe for weight loss-weren't losing weight. The runners, for example, ate an average of 200 to 400 fewer daily calories than they were burning, and some of these athletes reached points during the day when, because they were performing intense exercise without having eaten recently, they dipped into a caloric deficit of up to 1,100 calories for a few hours. But these exercisers were not losing weight, as you'd expect; in fact, they were among the "fattest" of the bunch. The reason, suspects Benardot, is that when deprived of food, even for just a few hours, the body desperately clings to any calorie it gets.

II THWART THE FAT-STORAGE INSTINCT

To elaborate on the calorie-clinging theory, Benardot explains that if you expend lots of extra energy when the body is underfed, the fuel the body needs in the form of liver and muscle glycogen (stored carbohydrate) is nowhere to be found. To cope, the body takes the irregular step of converting proteins in muscle tissue into blood glucose that it can use for energy. In other words, exercise on a long-empty stomach and you'll lose and weaken muscle.

And there's more. Since the body senses that food is in short supply, it shifts into starvation mode, which means that the next time you eat, there will be a larger-than-normal insulin response in an effort to capture the calories coming in. That, and the fact that the fat-storing enzyme, lipoprotein lipase, revs up higher than usual, results in a greater number of the newly ingested calories being tucked away as fat. "Now," the body thinks in its infinite yet out-of-date wisdom, "I'll be prepared for future times of famine."

One other factor that may determine why some people who go several hours without meals or snacks tend to have more body fat is that infrequent eating impairs appetite regulation, and that can lead to bingeing. Moreover, those who don't snack tend to play catch-up by eating oversize meals. "When you gorge after long periods without eating, the body is overloaded and becomes even more efficient at storing the extra calories as fat," explains John Ivy, PhD, a physiologist at the University of Texas and co-author of Nutrient Timing (Basic Health, 2004).

III DETERMINE WHAT YOU NEED, WHEN

Benardot's research demonstrates that it's key not to hit a calorie deficit or a calorie surplus greater than 300. Of course, short of living in a laboratory, there's no surefire way to know your exact energy-balance status at any given time. But you can avoid oversize deficits and surpluses by eating small- to moderate-size meals every three to four hours. And if you're going to work out in intense or long exercise sessions, eat more before and during to compensate. "If you ate a few hours earlier but are about to take a spin class followed by a weight-lifting session, you need enough fuel during that time to avoid diving into energy deficit," says Karen Dolins, EdD, RD, a nutrition professor at Columbia University in New York City and a nutritionist who follows these guidelines with her clients. "So burning around 700 calories doing a 90-minute workout means you need about 400 before and during so that you don't accrue a deficit of more than 300 calories."