Sports nutrition: Eating before exercise

While the pre-event meal is a key element to performance, fueling muscles and being well hydrated before exercise sessions will give Marc, Lauren and Anne the edge to train hard throughout the weeks leading up to Bayshore

How often do you head out for your training run first thing in the morningâ?¦before breakfast? Should you avoid eating before exercise if you are trying to lose weight? Does eating before exercise leave you feeling shaky, or with an upset stomach? While the pre-event meal is a key element to performance, fueling muscles and being well hydrated before exercise sessions will give Marc, Lauren and Anne the edge to train hard throughout the weeks leading up to Bayshore. Experimenting with food and drinks during training will also help them determine the best timing and tolerance for pre-exercise and pre-race foods.

Goals of nutrition before exercise include:

  • Consume a carb rich meal or snack in time to top of muscle stores

  • Choose foods that are easy to digest

  • Include a small amount a protein to help reduce post-exercise muscle soreness

  • Consume enough fluids to start the session in fluid balance

  • Practice â?? figure out what foods work best for you so that you have confidence in what to eat and when, to fuel training or competition

Fueling your brain, as well as your muscles, gives you mental stamina and focus to optimize training. While your body uses a greater share of fat for fuel while exercising in a fasted state (8 hours since your last meal) compared to doing the same workout after a carb-rich meal or snack, studies show that people are able to exercise harder and for a longer period when they consume carbs before exercise; training without pre-exercise fuel leads to decreased performance and early fatigue.

Overall, being able to exercise longer, at a higher intensity, will result in greater energy use (more calories burned), which is needed to cause fat loss. Consider the goals of your session to decide whether to eat or not before exercise. If your primary goal is to improve performance, have something to eat before exercise. If your primary goal is weight loss, as long as you will do the same amount of exercise (burn the same amount of calories, but over a longer time/distance), it is ok save your meal until after the session.

When to eat

Food eaten before exercise is only useful once it has been digested and absorbed. What and how much you eat affect how quickly you digest and absorb food. This means you need to time your meals and snacks so that the fuel is available during your exercise session. A general guide is to have a meal about 3-4 hours before exercise or a lighter snack about 1-2 hours before exercise. That said, itâ??s not always practical to eat a meal 3-4 hours before exercise. If any of the Three Amigos train early in the morning, they should choose a light snack about an hour before, even if it means getting up just a little earlier. For example, a glass of milk or juice and then some fruit or a cereal bar on the way to training can top off fuel stores. If scheduled for their long training run, Marc and Lauren can make up for their smaller carbohydrate intake prior to exercise by drinking a sports beverage during the event or training session.

What to eat

Food eaten before exercise should provide carbohydrate, be moderate in protein, and low in fat and fiber to make digestion easier. Foods higher in protein, fat and fiber tend to take longer to digest than other foods, and large amounts of food take longer to digest than smaller amounts. Too much food remaining in the stomach may increase the risk of stomach discomfort or upset during exercise.

While it has been suggested that low glycemic index (GI) foods* versus high GI foods** could be useful in maintaining a more stable blood sugar (glucose) levels during exercise, studies have been unable to show consistent benefits on exercise performance from eating low GI foods prior to exercise. Also, a study has shown that consuming carbohydrate (e.g. sports drink) during exercise overrides the effects of different types of carbs consumed before exercise. And many low GI options (lentils, legumes, multigrain bread) may not be suitable as if they slow digestion and cause stomach discomfort.

When the start of exercise overlaps with extra carb intake, it is usual to see a small dip in blood sugar levels. In most people, this is a temporary dip, which is quickly corrected by the body without any side-effects. If you experience a drop in blood sugar levels and symptoms such as fatigue, shakiness and dizziness after consuming carb immediately before exercise, try allowing a longer period between eating and exercising - experiment to find the best timing for your pre-exercise meal. Other tips include:

  • Choose a snack that provides at least 70 g of carb; small amounts of carb ({<}50 g) are more likely to cause problems in sensitive individuals than larger amounts. A higher carb intake will override a greater rate of use, leaving a net gain in available carbohydrate.

  • Include some lower GI foods (yogurt, pasta, oranges) in your pre-exercise meal

  • Include some high-intensity activity in your warm-up to help to stimulate extra energy release from the liver preventing blood sugar levels from dropping too low.

  • Consume carb during the event.

To fuel up before exercise, the Three Amigos should experiment to find the timing, amount and make up that best suits their individual needs. Some pre-exercise food and fluid ideas are:

3-4 hours

before exercise:

  • Toast with peanut butter and jam or honey + flavored milk or instant breakfast drink

  • Oatmeal with brown sugar and walnuts + skim milk + banana

  • Fruit and yogurt smoothie + low-fat granola

  • Low fat cottage cheese (1%) + apple butter + crackers or pretzels + grapes

  • Ready-to-eat breakfast cereal + skim milk + fruit

  • Baked potato + low fat (1%) cottage cheese filling + fruit

  • Turkey and Swiss sandwich + apple + sports drink

  • Low fat tuna sandwich + fruit cup + fat free yogurt

  • Pasta or rice with a tomato based sauce + vegetables + lean meat

    • hours

      before exercise:

  • Liquid meal replacement (Ex. Slim Fast drink mix, Boost etc.


  • Fat free yogurt fruit smoothie

  • Sports bars (check labels for carbohydrate, protein and fat content)

  • Low fiber ready-to-eat breakfast cereal (ex. Cheerios, corn flakes etc.) + skim milk

  • Low fat, low fiber cereal bar

  • Fruit-flavored yogurt

  • Less than 1 hour

    before exercise:

  • Sports drink

  • Sports gel, sport beans or gummies, sports bar

  • Piece of fruit or squeezable fruit pouch

  • Jam sandwich (white bread)

  • The type of exercise, duration, intensity, individual training status, and tolerance will affect the right pre-exercise meal plan for you. Consider working with a registered dietitian who specializes in sports nutrition for a meal plan that is personalized to your body, your sport, your stage of training, and your goals. Contact Miranda Monroe via for a consultation to put the science of sports nutrition on your plate with a personalized plan and practical meal planning strategies to help you achieve your performance goals.


    Foods that cause a slower, sustained release of sugar (glucose) to the blood


    Foods that cause a rapid, short-lived rise in blood sugar

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