Fuel Up: the Importance of Eating Before a Workout

Poor eating habits can undermine even the best efforts to stay fit.  Savvy athletes know that eating the right foods before a workout can give you the necessary fuel to make it through the last ten minutes on the treadmill or through that last set of squats.

So, what should you eat before you hit the gym? While every body is different, you can follow the guidelines below to stay strong even during your toughest workout. InsideTracker can provide suggestions of foods that are good for fuel AND help you optimize your biomarkers.



Eat carbohydrates for energy

People often assume that the best fuel for exercise—especially strength training—is protein. While protein plays an important role in muscle building and repair, carbohydrates are actually what keep your body energized during long workouts.

Carbohydrates are one of your body’s best fuel sources due to the efficient way they use oxygen. In fact, they use less oxygen for every kilocalorie of energy produced than either fats or proteins, which make them an important part of your diet if you are physically active, especially if you are an endurance athlete. So, how exactly does your body use carbohydrates?

The glycogen stores in your liver and muscles depend on your carbohydrate intake. Your body converts glycogen to glucose (a type of sugar), which your muscles use as a primary source of fuel during exercise. This means that your ability to exercise is limited by the amount of glucose in your body. After about 90 minutes of exercise, your body’s supply of glycogen is completely depleted, which puts you at a risk for “hitting the wall”, or feeling lethargic during your endurance event. If your body doesn’t have enough glycogen to sustain you, it will start to burn fat for energy. Fat burns at a much slower rate than carbohydrates, which will slow you down. All the more reason to eat some carbs before working out! InsideTracker can help you find the sources of healthy carbohydrates to meet your fitness and nutrition goals.

Eat protein for recovery

To repair muscle damage, your body needs protein, which is made up of amino acids, the building blocks for your muscles. An adequate supply of protein will help your muscles recover from workout stress, especially if you engage in weight-bearing exercise, such as weight-training or jogging. Including some protein in your pre-workout meal may help reduce post-exercise muscle soreness.

Eat healthy fats for endurance

Many people try to limit the amount of fat in their diet, but cutting it out completely can actually hinder athletic performance. Fat provides fuel for the body. If your workouts typically last more than an hour, your body uses fats for energy after your glucose supply has been depleted. However, you should keep in mind that some fats are more beneficial for people than others. Studies show that saturated and trans fats raise total blood cholesterol levels and low-density lipoprotein (LDL), or your “bad” cholesterol levels.  However, monounsaturated and polyunsaturated fats, found in many plant-based foods and oils, play a critical role in your body by helping to regulate oxygen, hormone restoration, cardiovascular health, and immune system integrity.

Like carbohydrates, fats are an important source of fuel for the body (they contain 9 calories per gram, compared with 4 calories per gram in carbohydrates and protein). While calories from fat aren’t as accessible as carbohydrates to athletes performing quick, intense efforts like sprinting, they play an important role in lower intensity and endurance exercise such as light bicycling or jogging.

Don’t run on empty!

Many people don’t like to eat before working out—especially if they exercise early in the morning—because they’re afraid of cramping. While it’s true that exercising on a full stomach can cause some people to experience nausea, muscle cramps, or lethargy, not eating beforehand may make you feel light-headed, weak, or sluggish because your body doesn’t have enough fuel to sustain you during exercise.

If your workout is more intense than a brisk walk or a light jog, you might want to opt for easy-to-digest carbs like a banana, toast, or oatmeal to provide keep you energized. If you’re the type of person who is typically hungry in the morning when you wake up, be sure to grab a small snack before an AM workout.

Timing is everything

You need to allow time for the foods you eat before your workout to be digested and absorbed. Plan your meals and snacks so that the energy that they provide is readily available when you exercise. The time your body needs to digest depends on the type and quantity of the food that you consume. Generally, foods that are high in protein, fat, and fiber take the longest to digest, and the same is true with large meals.

While you shouldn’t be famished when you exercise, it’s equally important to leave enough time before your workout to allow your body to digest. In general, larger meals take 3-4 hours to digest, smaller meals can take up to 3 hours, and small snacks can take as little as 30 minutes. However, every body is different, so try experimenting with your eating and exercise schedule to find out what works best for you.

What are some good pre-workout meals?

If you’re planning a meal a few hours before you exercise, try eating a combination of carbohydrates, protein, and fat.

3–4 hours before exercise:

Lean hamburger on a bun and some mixed yogurt and fruit – red meat is an excellent source of iron and protein, and serves as a perfect compliment to the vitamins and minerals that are found in the fruit. Hummus sandwich on pita bread with carrots – this protein-and-carb combination will help keep you satisfied during a long workout. Sweet potatoes and kidney beans – sweet potatoes are high in carbs, fiber, and vitamin A, while kidney beans will provide you with the protein that you need for muscle recovery.

2-3 hours before exercise:

Oatmeal with brown sugar, almonds, skim milk, and a banana - oatmeal is a great choice for long runs because it helps keep you satisfied without weighing you down Peanut butter & honey on toast – this snack is popular among vegetarian athletes because peanut butter is an excellent source of protein.

As your workout time draws closer, opt for a meal that is heavier on carbohydrates with a little bit of protein to help you feel satisfied and energized.

30–60 minutes before exercise:

Low-fiber cereal with skim milk – while fiber is a healthy part of any diet, it often causes many people to feel queasy right before a workout. Since muscles can convert simple carbs into energy faster than fiber-rich foods, try low-fiber cereal if you’re eating right before exercise. Low-fat yogurt with banana – bananas are an excellent source of both potassium and carbohydrates, while the yogurt provides your body with the sugar and protein that it needs to stay energized.  Hard-boiled eggs – not only are eggs a great source of protein, but this low-calorie snack is also a great choice for people who are watching their weight.

A balanced pre-workout meal will help sustain you through your exercise, and InsideTracker can help you learn how!