Scheduling exercise into a busy lifestyle can be a challenge, and planning meals and snacks around the exercise is another. Eating too much food, or the wrong food before exercise, can hamper your performance or cause indigestion, sluggishness, nausea and vomiting. On the other hand, if you haven't eaten in six hours and try to work out, you may feel weak and unmotivated. The type and time of meal is important. A large breakfast may be troublesome if you are going for a morning run, but it is fine for a jog before lunch.

In terms of food, your goal should be to have fuel in your body from nutritious food that is no longer present in your stomach at the time of your workout. The pre-exercise food prevents hunger during exercise. Carbohydrates are easily digested, but foods high in protein and fat may linger in the stomach for some time, depending on how much you ate. Large meals can take up to six hours to empty from the stomach.

Snacks, depending on their content, take about an hour to leave your stomach. Eating a high-carbohydrate snack two hours before exercising can leave you ample energy and a calm stomach for a great workout. Many athletes avoid food within two hours of a very hard workout, but can tolerate a lighter snack within one to two hours of a light workout.

Pre-Exercise Eating Tips

Experiment with your eating schedule to see what works best for you. Keep these tips in mind:

  • A high-carbohydrate, low-fat snack is easily digested and normalizes blood sugar.
  • Avoid fatty meals or snacks, because they may stay in your stomach for long periods of time.
  • Meal should be moderate in protein, i.e., just enough to satisfy hunger.
  • Drink lots of fluids. Your snack can be a liquid meal such as a fruit shake.
  • A light workout can be preceded with a light snack, but leave more lead time for intense workouts.

Depending on how heavy a meal you have eaten, wait at least 30 minutes to two hours before exercising. The bigger the meal the longer you will need to wait. If you just eat a light snack such as pretzels or a fruit drink, you should be ready to work out within 30 minutes.

Eating and Your Exercise Routine

If you exercise first thing in the morning, some fruit or a small amount of juice and water should suffice. If you exercise mid-morning, then a breakfast high in carbohydrates will help give you the energy you need to get through your workout. A bowl of oatmeal, wholegrain toast and jam are good choices. If you exercise in the late morning before lunch, you may want to try eating a light snack before working out and then a carbohydrate- and protein-rich lunch (such as a turkey sandwich) that will replenish your body stores after you exercise. People who work out later in the afternoon, from noon to 3 p.m., probably do not have to eat anything before a workout provided they have eaten a well-balanced lunch and breakfast. However, if you exercise closer to dinner, a light snack, like a bowl of yogurt or fruit, will provide some energy. When exercising after dinner, just make sure to wait an appropriate amount of time depending on the size of your meal.

Do What Works for You

The above recommendations are guidelines. Each individual is different and has a unique digestive system, so you have to experiment to see what makes you feel best during your workouts. Some days you feel great if you work out soon after a meal, whereas other days you might get cramps and feel nauseous. It varies from person to person and day to day.

Keep a Food and Exercise Diary

Write down what you eat, when you ate it and how you feel during your workouts. This will help you pinpoint the foods that enhance your performance and those that make you feel sluggish. You'll find certain foods work for you and others, no matter how good for you nutritionally, just will not cut it.

Post-Exercise Eating Tips

Eat foods rich in carbohydrates during the hour or two following your workout and you should be enhancing your energy reserves for the next day's workout. Also, after you exercise, drink plenty of water to rehydrate your body. Research shows that fatigue during exercise can be related to low levels of water and stored carbohydrates. Since we use carbohydrates as energy during exercise (including many forms of resistance training), we need to replenish these storage depots after a workout. This will assist weight trainers but is especially important for people who do a lot of aerobic exercise (more than 60 minutes) on consecutive days.

In addition, consumption of protein is necessary during your post-exercise meal. It will help rebuild the tissues damaged during your workout. In addition, protein will facilitate carbohydrate storage to improve recovery if it is consumed with carbohydrates during the initial two hours after a workout.

Greg Shealey is a health educator and president and founder of Bio-Fit and Wellness.