Usually not. If you’re eating a healthy diet and getting enough calories to support your activity level, you can probably rely on your own appetite, energy levels and experience to tell you whether you need to eat anything before or after exercise and what it should be. The basic rule here is: Find out what works best for you, and do that.
There are some advantages to knowing how your body works and what it needs to perform at its best. The bottom line for healthy weight loss and fitness sounds simple: You have to eat fewer calories than you use up—but not fewer than your body needs to function at its best.
The size, timing and content of your pre- and post-exercise meals and snacks can play an important role in your energy levels during your workout, how well your body recovers and rebuilds after your workout and whether the calories you eat will be used as fuel or stored as fat. Here’s what you need to eat and drink to get the results you want!
Your Pre-Exercise Fluid Needs
Being well-hydrated will make your exercise easier and more effective. Try to drink 16-20 ounces of water during the one or two hours before starting your workout.
Your Pre-Exercise Meal or Snack
News flash: Most of the fuel you use during exercise doesn’t come from the food you’ve recently eaten: It actually comes from the carbohydrates (called "glycogen") and fat that’s stored in your muscles, liver and fat cells. That’s enough to fuel one or two hours of very intense exercise or three to four hours of moderate-intensity exercise.
This means that if your overall diet is adequate to keep your fuel tanks topped off, you may not need to eat anything before you work out. So, if eating before exercise upsets your stomach or you like to exercise first thing in the morning or at a time when eating first isn’t convenient, don’t feel like eating first is a must.
Some people do have a hard time exercising without eating first, especially if it’s been a long time since their last meal or snack. These individuals often are more sensitive to changes in their blood sugar levels, which fall during the first 15-20 minutes of workout. That drop in blood sugar can cause tiredness, mild dizziness or even faintness—especially if your blood sugar was already low—but eating something beforehand can help prevent this. If you have health issues like diabetes or hypoglycemia that can cause low blood sugar, you’ll probably want to eat before your workout. If you get very hungry during a workout (and it interferes with your energy levels or focus), or become so ravenous after an exercise session that you end up overeating, try eating before you hit the gym to avoid these problems.
If you are a moderate exerciser who tends to perform better with a pre-exercise snack, there are two ways to handle your needs:
1. Eat a small (100- to 200-calorie) snack about 30 minutes before you work out. This snack should include fast-digesting (high glycemic index) carbohydrates and very little fat (which digests slowly), so that you digest the meal quickly and the fuel is available during your exercise session. Here are some ideas:
- Fruit juice
- Fruit smoothie
- High-glycemic fruits like pineapple, apricots, banana, mango and watermelon
- Sports drinks
- Pretzels or bagels (but not whole grain varieties, which digest slowly)
- Energy bars (look for 3-5 grams of protein, at least 15 grams of carbs and very little fat)
- Fruit and yogurt
- Nuts
- Oatmeal
- Cereals (with more than three grams of fiber) and milk
- Trail mix with nuts and dried fruit
- Hummus and raw veggies
- Hard-boiled eggs (or egg whites)
- Cottage cheese and fruit
- Half a peanut butter or turkey/chicken sandwich on whole-grain bread
- Whole-grain crackers with nut butter or cheese
- Whole grain fig (or fruit) Newton cookies
- Milk (especially chocolate milk)
- Tomato or vegetable juice
- Yogurt smoothie (with added protein powder, if desired)
- Most protein/energy bars
