Exercise Snacks: To Eat or Not to Eat
by Nancy Clark, MS, RD

Certainly, pre-exercise foods that settle comfortably can enhance stamina, endurance, strength, and enjoyment. But with the possibility that pre-exercise food can create intestinal chaos, the threat of diarrhea can turn the thought of pancakes into panic. Adverse reactions occur in 30 to 50 percent of endurance athletes. Complaints include stomach and upper gastrointestinal (GI) problems (heartburn, vomiting, bloating, heaviness of food, and stomach pain) and intestinal and lower GI problems (gas, intestinal cramping, urge to defecate, loose stools, and diarrhea). You should know about some of the predisposing factors for GI problems:

¥ Type of sport. Cyclists, swimmers, cross-country skiers and others who exercise in a relatively stable position report fewer GI problems than do athletes in sports that jostle the intestines.

¥ Training status. Untrained people who are starting an exercise program report more GI problems than do well-trained athletes who have built up tolerance to exercise. If you are a novice who is experiencing GI distress, gradually increase your training volume and intensity so that your body can adjust to the changes.

¥ Age. GI problems occur more frequently in younger athletes than in veterans, because the younger athlete may be less trained and possibly have less nutrition knowledge and experience with precompetition eating. Veterans, on the other hand, have had the opportunity to learn from years of nutritional mistakes.

¥ Gender. Women, as compared with men, report more GI problems, particularly at the time of the menstrual period. The hormonal shifts that occur during menstruation can contribute to looser bowel movements.

¥ Emotional and mental stress. Athletes who are tense are more likely to report that food in the stomach lingers longer and settles like a lead balloon.

¥ Exercise intensity. During easy and even moderately hard exercise, the body can both digest food and comfortably exercise. But during intense exercise, the shift of blood flow from the stomach to the working muscles may be responsible for GI complaints.

¥ Precompetition food intake. Eating too much high-protein and high-fat food (such as bacon and eggs or greasy burgers) shortly before exercise can cause GI problems. Tried-and-true low-fat, carbohydrate-rich favorites (such as oatmeal or bananas) that are part of your day-to-day training diet are a safer bet.

¥ Fiber. High-fiber diets intensify GI complaints. If you are eating large amounts of bran cereal or high-fiber energy bars, try cutting back for a week to see if you feel better.

¥ Caffeine. Some athletes seek enhanced performance from drinking a larger-than-usual mug of coffee but end up with an upset stomach, diarrhea, and substandard performance.

¥ Gels and concentrated sugar solutions. Highly concentrated sugar solutions consumed during exercise may cause stomach distress. Don't confuse the high-carb recovery drinks (about 200 calories per eight ounces, or per one-quarter liter) with low-carb fluid replacers.

¥ Level of hydration. Dehydration enhances the risk of intestinal problems. During training, be sure to practice drinking different fluids on a regular schedule (eight ounces every 15 to 20 minutes of strenuous exercise) to learn how your body reacts to water, sports drinks, diluted juice, and any fluids that you will be drinking during competition.

¥ Hormonal changes that occur during exercise. The digestive process is under hormonal control, and exercise stimulates changes in these hormones. For example, the postmarathon levels of GI hormones in marathon runners tend to be two to five times higher than resting levels. These hormonal changes can result in food traveling faster through the digestive system and explain why some people experience GI problems regardless of what they eat.

Energy Bars: Costly but Convenient

PowerBars, PRBars, Zone Bars, Balance Bars-a plethora of energy bars await you at every convenience store, each boasting its ability to enhance your performance. You can spend a fortune on these prewrapped bundles of energy, thinking they offer magic ingredients (not true). Here is some information to help you decide how much of your food budget to dedicate to these popular snacks.

¥ Energy bars are convenient. In today's eat-and-run society, when meals are a rare occurrence in a busy schedule, an energy bar suits the need for many hungry people who seek a hassle-free, somewhat nutritious snack.

¥ Energy bars are portable. You can easily tuck these compact and lightweight vitamin-enriched bars into a pocket for "emergency food." Energy bars are handy for runners and bikers who want to carry a durable snack on a long run or ride, or for hikers who want a light backpack.

¥ Energy bars promote pre-exercise eating. Snacking before exercising is a great way to boost stamina and endurance. The energy bar industry has done an excellent job of educating us that pre-exercise eating is important in optimizing performance. The associated energy boost likely does not result from magic ingredients (chromium, amino acids) but from eating 200 to 300 calories. These calories (which usually include some form of sugar) clearly fuel you better than the zero calories in no snack. Note that calories from tried-and-true fig bars, graham crackers, bananas, and granola bars are also effective pre-exercise energizers.

¥ Energy bars promote eating during endurance exercise. Energy bars are also a great way to boost stamina and endurance. Instead of relying on what you eat before you exercise, you can consume about 0.5 grams of carbohydrate per pound of body weight per hour during endurance exercise. This comes to 200 to 300 calories for most active people-exactly what an energy bar offers.

¥ Most energy bars claim to be highly digestible. One could debate whether energy bars are easier to digest than standard food, because digestibility varies greatly from athlete to athlete. I've heard some people comment about how a PowerBar settles heavily in the stomach, whereas others swear it is the only food they can tolerate during exercise. As with all sports snacks, you have to learn through trial and error during training what foods work for your system and what foods don't. Do not try this pricey treat for the first time before a special event, such as a marathon, bike race, or rugby game only to discover it causes discomfort. One key to tolerating energy bars is to drink plenty of water along with the bar. Otherwise, the product will settle poorly. Energy bars have a very low water content to make them more compact than fresh fruit, for example, which has high water content.

¥ Some energy bars are touted as fat free or very low in fat. The claim is that they digest quickly and empty from the stomach without causing problems. ¥ Some energy bars boast about a higher fat content. A higher fat content supposedly promotes greater fat burning to help you lose body fat and exercise longer before you hit the wall. To date, I know of no professional research that suggests that pre-exercise fat enhances weight loss.

One possible advantage to including a little fat in the pre-exercise snack may be to provide sustained energy. A little fat can provide longer lasting energy for people who will be exercising for more than 90 minutes, such as long-distance bikers, runners, or cross-country skiers. The value of the pre-exercise fat will vary according to individual tolerance. ¥ Energy bars are expensive. You'll have to fork over at least one dollar, if not two, to buy most sports bars. The better value is to buy low-fat granola bars or breakfast bars from the supermarket at a much lower price. A handful of raisins can also do a great job at a low price.

Fast, Healthy, Natural Snacks

When you are eating on the run and grabbing snacks instead of real meals, be sure to choose wholesome foods for these minimeals. You can make wise choices from among many nutritious and conveniently available items. Some popular suggestions include: whole-grain bagel with peanut butter and a yogurt; thick-crust pizza with green peppers; peanut butter, crackers, and V-8 juice; trail mix with nuts and dried fruit; granola with low-fat milk and banana; Chinese takeout-stir-fry chicken with vegetables and steamed rice; and instant oatmeal made with low-fat milk.

Note that each of these minimeals includes foods from at least two food groups. Ideally, you'll choose foods from different groups to help balance your diet. That way, even people who graze throughout the day can get a variety of nutrients needed for good health and top performance.

Here are additional ideas for snacks and grazing at home and on the road: Mix your favorite cereal with raisins, dried fruits, cinnamon, or nothing! Microwave instant oatmeal in milk instead of water to boost its nutritional power. Sprinkle with raisins and chopped nuts; Eat plain popcorn or sprinkle it with spices such as chili powder, garlic powder, onion powder, or soy sauce. If you like, spray with low-calorie butter flavor sprays so that the spices stick; If you wish to reduce your salt intake, scrape off the salt or buy salt-free pretzels. Crackers made from stoned wheat, sesame, bran, and other reduced-fat or fat-free brands are good choices; Homemade muffins with canola oil are best. If store bought, choose low-fat muffins; wholesome bran or corn muffins are better than those made with white flour; Whole-grain bagel varieties provide more vitamins and minerals than do bagels made with white flour; Choose oranges, bananas, apples, or any fresh fruit. When traveling, pack along dried fruit for concentrated carbohydrates; Whip together milk or juice, fresh or frozen fruit, and wheat germ or flax meal for nutritious smoothies; Frozen fruit bars are delicious, nutritious treats; Buy plain low-fat yogurt and flavor it with vanilla, honey, cinnamon, instant decaffeinated coffee, applesauce, fruit cocktail, or berries; Energy bars, breakfast bars, low-fat granola bars travel well in pockets and gym bags and can be very handy; Peanuts, pistachios, almonds, sunflower seeds, pumpkin seeds, and other nuts and seeds are excellent for protein, B vitamins, vitamin E, and healthful fat; Sandwiches don't have to be just for lunch; they are great for snacks. Use peanut butter, turkey, hummus, lean roast beef, or tuna with lite mayo; Microwave ovens make baked potatoes a handy snack. They're tasty warm or cold, and because of their high glycemic effect, they are excellent for refueling your muscles after a hard workout. Try sweet potatoes with a dash of nutmeg-mmm!

Nancy Clark is author of the best-selling book "Nancy Clark's Sports Nutrition Guidebook, Third Edition" (Human Kinetics; 2003; $18.95; www.humankinetics.com). To order the book call 217-351-5076 or buy it from your local bookstore.