Boy and SheepCreative Commons License Peretz Partensky via Compfight

The goal of the pre-workout snack for any aerobic activity lasting more than an hour is to maintain a constant glucose source for your muscles, so you don’t dip to far into your glycogen stores. Just as a car sputters to a stop when it runs out of gas, you “hit the wall” or ‘bonk’ once glucose supplies are drained and no snack after that will rev your engine in time to finish the workout. To prevent hitting the wall, your pre-workout snack should include:
1) Water, to ward-off dehydration, especially if it is hot outside.
2) Easy-to-digest, quality carbs that leave the GI track quick, yet supply the glucose you need to fuel your workout. Go for snacks (and your diet overall for that matter) that are about 60% carbs, since this is the level of carb intake that maximizes glycogen storage.
3) A bit of protein from yogurt, milk, soymilk, or nuts to off-set a rapid drop in blood sugar from eating carbs alone, and to aid in repairing and building of muscle.
4) Light and low-fat – say 100 to 200 calories – to avoid digestive problems. The size of the snack varies from person to person, so it’s best to err on the side of caution by eating less at first and make adjustments as you go. Easy-to-digest, carb-protein combos include:
o   half a whole wheat bagel with a little low-fat cheese,
o   a soft pretzel with nonfat yogurt
o   whole wheat toast topped with apple butter and fat-free cottage cheese
o   small helpings of leftover rice or pasta dishes
o   a small slice of last-night’s vegetarian pizza
o   oatmeal cooked in nonfat milk with maple syrup and a banana
o   string cheese with apples and whole-grain crackers
o   a small bowl of whole-grain cereal with light soymilk