When and What to Eat Before Exercise
Exactly how much carbohydrate and fluid you should consume and at what time depends on your sport and individual tolerances. The general guidelines for both fluid and carbohydrate intake are summarized and suggest that athletes drink approximately 1.5 to 2.5 cups (354-590 ml) of fluid two to three hours before exercise and consume either a large carbohydrate meal (providing 3 to 4 grams of carbohydrate per kilogram of body mass) three to four hours before exercise or a smaller meal or snack (providing 1 to 2 grams of carbohydrate per kilogram of body mass) one to two hours before exercise.
As an example, a 90-kilogram(198 lb) male track athlete who eats breakfast 90 minutes before exercising should consume between 90 and 180 grams of carbohydrate in his pre-event meal. A60-kilogram (132 lb) female cyclist should consume between 60 and 120 grams of carbohydrate one to two hours before an early-morning training ride, and between 180 and 240 grams four hours or so before a late-afternoon training ride.
A sample pre-event meal that provides 90 grams of carbohydrate and focuses on low-GI foods is provided. In addition, evidence shows that consuming a well-tolerated carbohydrate source, such as a fluid-replacement beverage or piece of fruit with a few sips of water, 5 to 10 minutes before exercise will further benefit performance during prolonged or intense exercise. Research has shown that carbohydrate consumed with adequate water immediately before exercise provides benefits similar to carbohydrate consumption during exercise.Another guideline for the pre-event meal is to consume only familiar, well-tolerated, high-carbohydrate foods that are low in sodium, simple sugars, and fiber and don’t contain excess spice.
Experimenting with a new food or product is fine as long as you experiment during training or practice and preferably not an important one. If you are accustomed to eating gas-producing foods such as legumes and they offer no ill effects—go for it! Again, these and other low-GI foods may offer a performance advantage over higher-GI foods by providing a slowly released form of glucose during exercise. On the other hand, gas-producing and high-fiber whole-grain foods may not be as readily emptied from the gut and may contribute to nausea or diarrhea. This is particularly a concern if you get a “nervous stomach” or typically have problems defecating before competitions.