Unsure what to eat before a workout? There’s a real science to what passes your lips before training: typically, you’ll want to consume slow-release carbs for longer endurance sessions and you’ll need fast-release carbs for short, intense workouts.

But what counts as a slow-release or fast-release carb? And how do other macronutrients, like protein and fats, help during training? We asked a group of qualified nutrition experts to explain.

What should you eat before a workout?

Pre-training nutrition should be determined by the type of exercise you plan to do and the physiological adaptation you’re trying to achieve – like gaining muscle or losing weight. But carbs are best for providing energy.

If you favor exercises like HIIT, weightlifting, or power training, you should attempt to prioritize quick-releasing high-glycemic carbs that spike sugar levels for a quick energy release. Think instant oatmeal and sports beverages. If you prefer low-intensity endurance exercise like longer runs, slow-release carbs planned a few hours to an hour in advance will help sustain energy release over time. Think quinoa, whole grains, sweet potatoes, and pulses in this case.

Rob Hobson, Head of Nutrition at Healthspan Elite, recommends consuming something quick-digesting before your standard workout – like toast with peanut butter, an oat smoothie, or a banana. But for a long race lasting more than an hour, Hobson says you should ideally plan carb intake more carefully, “aiming for up to 4g of carb per kg of body weight, which means eating several meals starting four hours before you hit the start line”.

Jamie WrightSocial Links Navigation

Accredited nutritionist

Jamie Wright is an accredited nutritionist, with a BSc in Sports and Exercise Science and an MSc in Human Nutrition. He's currently the head nutritionist at Balance; a team of fully qualified nutritionists and dieticians working with everyone from office workers to Olympic athletes.

When should you eat before a workout

Most advice states that you should eat two to three hours before a workout. A small study, published in Nutrients Journal, compared the effects of a six-hour versus three-hour pre-feeding regimen in a group of eight active women. In general, performance results were more favorable for the three-hour group, suggesting that this really is the golden time for loading up with food.

However, it’s not always possible to adhere to this two-to-three-hour rule. “If you have an early morning training session (especially if you don’t fancy eating before your session), having a carbohydrate-rich meal the evening before can still help give you the energy you need,” suggests Hobson.

Should you eat after a workout?

If the thought of eating before you train turns your stomach, there could be some benefit to skipping on a feed altogether. Brian Carson, head of science and innovation at Whole Supp and a senior lecturer in exercise physiology, tells Live Science that exercising following a period of fasting can promote adaptation towards your body’s ability to utilize fat as a fuel source.

“We have previously published a systematic review and meta-analysis at the University of Limerick examining this approach and found a greater utilization of fat during exercise, with no negative impact on performance for exercise which lasts less than 60 minutes when performed in a fasted state,” he explains. “We also recently published research looking at restricting carbohydrates pre-exercise and feeding protein before high-intensity sprint interval training, and found that this was an excellent approach for this short intermittent type activity.”