The benefits of eating before a workout

Some swear by their pre-workout nutrition to maximize energy and performance, while others prefer fasted workouts for fat loss.

But is one better than the other, or does it depend on the type of workout? Let’s get into the science behind fueling (or not fueling) before exercise to help you decide what works best for you and your goals.

Eating before a workout provides readily available energy, preventing fatigue and maximizing performance.

And the type of fuel, or macronutrients, you should prioritize depends on several factors, including the amount of time you want to train, the intensity, and the type of exercise you want to perform.

Let’s first cover the basics of macronutrients and how they impact your performance:

Carbohydrates

Carbohydrates are one of the body’s main sources of energy. They are broken down into glucose, which your muscles can use for energy. Carbs are the primary fuel source for moderate to high-intensity endurance exercise and resistance training-based workouts.

Glucose is stored as glycogen in the liver and muscles and can be used for fuel during endurance exercise.

However, glycogen stores are limited and can be used up during exercise. This can impact your overall output and your ability to keep up the intensity.¹

Research suggests that for moderate or high-intensity exercise, it’s necessary to consume 1 to 4 g/kg of carbohydrates 1 to 4 hours before the physical activity. ²

Protein

Eating protein before a workout can improve performance and increase muscle protein synthesis. That’s because proteins are broken down into amino acids, essential building blocks for muscle fibers.

Protein is recommended before strength training to help build muscle, or cardio-endurance workouts to prevent muscle breakdown, especially if the activity will last more than 90 minutes.

Fat

Although glycogen is the preferred source of energy for moderate to high-intensity exercise, fat is the main fuel source for moderate to low-intensity exercise.

One study investigating the effects of a high-carb or high-fat meal 3.5 hours before exercise, after one week of carb loading, found that those who ate a high-fat meal had better glycogen stores after one hour compared to those who ate a high-carb meal.³

However, more research is needed. Fat takes longer to digest than carbohydrates, so if you eat too much fat before a workout, it can leave you feeling sluggish and impact your performance.

Eating before a workout is a particularly good idea when:

• the physical activity will last more than 60 minutes
• you are performing high-intensity workouts like high-intensity interval training (HIIT) or endurance activities
• your goal is to maximize muscle growth and strength
• you’re competing in a competition or aiming for peak performance
• you’re feeling tired, sluggish, or fatigued

It’s not just the type of training that matters, but also when. Timing is everything when it comes to eating before a workout.

For example, some research shows that women should eat about 90 minutes before exercise. This is more beneficial for burning fat than eating afterward.

Meanwhile, men looking to burn body fat should eat 90 minutes after exercise.⁴

And you can optimize the benefits even further by timing your meals. So, if you are going to eat:

• 2 to 3 hours before a workout, consider eating a meal consisting of carbs, protein, and fat, such as grilled salmon, half a sweet potato, and grilled vegetables
• within 2 hours of a workout, eating a smaller meal focusing on carbohydrates and proteins, like a cup of oatmeal, a banana, skimmed milk, and chopped almonds
• within 30 minutes to an hour of exercise, choose easy-to-digest foods and smaller portions like Greek yogurt and fruit, a banana, or a protein bar

To find what works for you, it’s important to experiment with different timings and nutrients.

Some people swear by fasted workouts to maximize those extra fat-burning benefits to lose weight. And while intermittent fasting (IF) does offer its own set of health benefits, it’s important to be aware of how working out on an empty stomach could impact your overall performance and goals.

To combine IF with your training schedule, try to time your workouts during eating windows when your nutrition is optimized to match your performance. If you’re planning on completing a workout fasted, stick to low-intensity training like yoga, walking, or a light mobility routine.

For medium to high-intensity workouts, your body requires fuel to perform at its best. But that’s not the only benefit eating before a workout offers. Here are some other key benefits that fueling before a workout can provide:

• Boosts energy levels, preventing early fatigue and helping sustain effort
• Enhances performance, maximizing strength, endurance, and focus
• Improves recovery by supporting muscle repair and replenishing glycogen stores
• Prevents muscle breakdown, which is particularly important for strength and endurance athletes
• Minimizes the risk of dizziness and fatigue by providing the energy needed to prevent lightheadedness, especially during more intense workouts

The types of foods or meals you should eat before a workout will depend on the activity you will complete. In short:

• Cardio training should focus on a higher carb intake like bananas, energy bars, or wholemeal toast with honey to make sure you have the energy you need to sustain your aerobic exercises.
• Strength training requires a combination of protein and a moderate carbohydrate intake, such as scrambled eggs in wholemeal toast, Greek yogurt with fruit.
• HIIT workouts mostly rely on carbohydrates to provide your body with the rapid energy it will need, and a small amount of protein to protect and build your muscles is also beneficial. Think oatmeal and banana, or wholegrain crackers with peanut butter and apple.
• Low-intensity workouts need a balance of all macronutrients, like nuts, fruit, and yogurt, or smashed avocado on wholemeal or sourdough toast.

So, in the great debate of fed vs. fasted workouts, which one is best? Ultimately, the one that works best for you.

It’s all about listening to your body, testing what works best for you with a bit of trial and error, and taking a personalized approach.

While it’s important to understand the pros and cons of eating before a workout, at the end of the day, you need to figure out what works best for your body and your performance goals.