The right fuel before you work out might can help you perform at your best.

Your body relies on a good store of carbohydrate to maintain blood sugar while you exercise – but after an overnight fast, those stores could be running low. So eating before a hard workout can help provide enough fuel for working muscles. There’s a practical reason for eating before a long workout, too – it keeps you from getting hungry while you work out.

What You Should Eat Before You Work Out

Since carbs are so important to your body’s engine, your pre-workout meal should be relatively high in carbohydrate. A little bit of protein is good, too. It will slow digestion just a little bit – enough to allow the carbs to enter the bloodstream a little more slowly and steadily. On the other hand, you don’t want to eat a lot of fat right before you head out – it can slow digestion too much and leave you feeling uncomfortably full. And save your high fibre foods for afterwards, too, since they also take a while to work their way through your system.

As far as what specific foods you eat – there are no hard and fast rules. A smoothie made with fruit, milk and protein powder works well if you’ll be working out relatively soon after eating; a turkey sandwich and a bowl of soup at lunch will be pretty well digested if you’re going for a run in the mid-afternoon. If you work out in the mornings but you just don’t like breakfast foods, then eat whatever appeals to you. Most people don’t see anything ‘wrong’ with eating a bowl of cereal for dinner, so why should it be ‘wrong’ to eat leftovers for breakfast?.
When You Should Eat Before You Work Out

There are specific guidelines for meal timing – but in reality, you have to go with what feels right. Some people can eat as usual just before exercising, while others prefer a lighter load in the stomach. Generally speaking, the longer you have to digest your meal before you start working out, the larger and more solid your meal can be.

If you’re going to be working out within an hour or so of eating, then you’ll want a small semi-solid or liquid meal that will empty from your stomach relatively quickly. A smoothie, for example, would be light and easy to digest. If you’re going to work out in the mid-afternoon, a regular, well-balanced meal at lunch should have you covered. If you’ve got a hard workout scheduled right before dinner, you’ll need a light snack in the mid-afternoon – a carton of low-fat yogurt with some fruit would work.

How Much You Should Eat Before You Work Out

Some athletes like to know the specifics of what they should eat before a workout – and the guidelines are very specific. Most people just use the ‘trial and error’ method until they figure out the eating schedule that works for them.

For those of you who want to know the details, here they are: athletes are advised to eat between 1 and 4 grams of carbohydrate per kilogram of body weight (or, 0.5 grams of carbohydrate per pound of body weight) one to four hours before exercising. The reason for the range is that it depends on how soon you’re going to exercise after eating. The longer you have to digest, the more you can eat at the pre-exercise meal.

1 hour to digest before exercise – 1 gram carbohydrate/kg body weight
2 hours to digest before exercise – 2 grams carbohydrate/kg body weight
3 hours to digest before exercise – 3 grams carbohydrate/kg body weight
4 hours to digest before exercise – 4 grams carbohydrate/kg body weight

Don’t Eat More Than You Burn

One final note – if your workouts aren’t particularly vigorous or lengthy, this advice may not apply to you. Not everyone needs to fuel up before exercising. If your routine consists of a 30-minute brisk walk in the morning, that’s a great regimen – but it’s also not so intense that you need to top off your tank before you head out.

Written by Susan Bowerman, MS, RD, CSSD. Susan is a paid consultant for Herbalife.