Whether you're a new gym goer or a seasoned athlete, the food you eat before your workout can have a significant impact on your performance and recovery. Eating the right foods at the right time can help you maximize exercise performance and prevent fatigue, no matter your fitness goal.
In this blog post, we’ll examine research on how to effectively fuel your body before working out and replenish its energy stores post-workout, while in a caloric deficit.
Understanding your macronutrients (macros)
Carbohydrates are important for providing energy to your body during exercise. When we eat carbohydrates, our body breaks them down into glucose, which is then used for energy or stored in the liver and muscles as glycogen. When we need energy, our body breaks down glycogen into glucose to fuel our activities.
Although they can be stored in your body, the amount that can be stored is limited (1). This means you need to eat carbohydrates throughout your day, and within your nutrition plan to maintain your energy levels.
Carbohydrates are also critical for your brain and nervous system to function properly during exercise. When you exercise at high intensities, you need more carbohydrates to provide energy to your muscles. If you don't have enough carbohydrates, you will feel tired and your performance can suffer (1).
Protein intake is also essential, as it is the primary driver of muscle protein synthesis. This is the process in which your body grows, maintains, and repairs muscle mass. When you work out, you create small tears in your muscle fibres. If your body can't synthesize enough new muscle fibres to replace the damaged ones, your muscles won't grow or repair as effectively.
You should hit a minimum protein intake target of 0.18g/lb bodyweight per meal across a minimum of 4 meals to reach a minimum of 0.73/lb bodyweight (3).
Fats are a nutrient-dense macronutrient, providing nine calories per gram compared to four calories per gram for both carbohydrates and protein. While fat provides more calories, it doesn’t provide the same amount of energy as carbs do, making carbs much more effective in providing the energy you need for exercise performance (1).
With this in mind, when fuelling your body prior to exercise, focus on your carbohydrate and protein intake.
What to eat before workouts
To determine what you should eat before working out, you must look at what time of day you’re planning to exercise. In addition, you’ll also evaluate what your own body needs in the tank before exercise, as you may need to eat a bigger meal in the morning while someone else may eat something lighter.
For those that exercise in the morning, you may need to eat a bit more as you haven’t given your body energy in some time. However, if you’ve eaten a large meal at night, you may be able to eat very little or fast for your workout.
If you’re on the go, I like to have a lighter meal with easy-to-eat carbs consisting of low fibre and fat within an hour of training. As I mentioned earlier, carbs provide our body with the fuel it needs for exercise performance.
Fibre-rich foods are great options for increasing your fibre intake but do slow the digestion rate. If you’re wanting to reach for high-fibre options such as oats, just be aware that it may take longer for your body to digest and create energy stores (4).
For example, if you’re up at 5am, but don’t plan to workout until 9am, you may find fibre-rich carbs, like oats, to be what you need. If you’re up and working out within the hour, try a protein smoothie.
Fasted workouts may work for you, but it would be dependent on what you’ve eaten the night before as well as the deficit you’re in. In general, when you exercise without eating anything beforehand, your body starts to break down muscle protein for energy. This can continue even after you finish exercising, which means that your body is in a muscle protein breakdown state.
Should you choose to work out while fasting, to switch your body to a muscle protein-building state, it's recommended to have protein and carbohydrates right after your workout (2). This will help promote muscle growth and reduce muscle protein breakdown.
Although there is evidence to show that having a pre-workout meal is superior for exercise performance in comparison to a fasted state, the overall amount of food eaten in 24 hours leading up to exercise is most important.
Afternoon & evening workouts
Whether you’re working out on your lunch break or after calling it a day, you will want to consider when you’ve eaten in your day, as you may not need to eat as much right before your workout.
Consuming foods that keep you full throughout your day should be a priority. This includes high-fibre carbs, such as oats, whole grains and vegetables, as well as quality proteins, like meat, fish, or Greek yogurt.
Depending on how much you’ve eaten and your food selection, you should find a larger meal 2-4 hours before working out sufficient. In this case, should you get hungry right after your workout, ensure your post-workout meal is protein- and carb-rich to support your energy and muscle maintenance systems (1,2,5).
Importance of hydration
In addition to eating the right foods, it's essential to stay hydrated before, during, and after your workout, as your body sends fluids to different parts of the body for different purposes (1,6).
For example, sweating is a normal part of working out, and your body does this to prevent it from overheating. While the amount of sweat you produce depends on factors like the intensity of your workout and the environment you're in, a 2017 study found adults can sweat between 0.5 to 4.0 litres per hour of exercise.
Other areas your body sends fluids to include:
the brain to provide it with nutrition and oxygen,
the heart and lungs to help with blood circulation and breathing, and
the muscles to provide them with nutrition and oxygen (6).
By staying hydrated, you can help your body regulate its systems and temperature, preventing things like overheating during exercise. There are no guidelines on how much water you should drink before, during, and after exercise, as the amount of water had in a day and the type of food consumed will vary from person to person.
For most people, the sensation of thirst is a great way to understand how much water your body needs. Thirst is triggered when your body sees an approximate 2% decrease in water weight, which subsequently goes away once a loss of 2% is restored (6).
During exercise, focus on alleviating thirst sensations, rather than over-drinking water by drinking enough water to balance your sweating. To effectively replace fluids after exercise, consuming up to 150% of the estimated amount of fluid lost during the workout is recommended within 4 hours or less (6). This extra fluid is needed to make up for the body's tendency to get rid of excess fluids after exercise.
Fuel your body
Overall, the most important thing to consider while eating before workouts while in a deficit is how much food you’ve eaten prior to exercise. If you’re working out in the morning, keep in mind that it’s been some time since you’ve eaten. If you’re working out in the afternoon or evening, consider how much you’ve eaten in the day overall, as you may not need to eat before a workout.
Another important consideration is individual variability. Since we all respond differently to exercise programs and eat different foods, some of these strategies may not work for you. While these methods have been studied in-depth, it’s critical to understand what your body needs pre-workout. Consultation with a fitness or healthcare professional may be beneficial if you’re looking for guidance on your unique needs.
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Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Nutrition and athletic performance. Med. Sci. Sports Exerc, 48, 543-568.
Aragon, A. A., & Schoenfeld, B. J. (2013). Nutrient timing revisited: is there a post-exercise anabolic window?. Journal of the international society of sports nutrition, 10(1), 5.
Schoenfeld, B. J., & Aragon, A. A. (2018). How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Journal of the International Society of Sports Nutrition, 15(1), 10.
Rebello, C. J., O'Neil, C. E., & Greenway, F. L. (2016). Dietary fiber and satiety: the effects of oats on satiety. Nutrition reviews, 74(2), 131–147. https://doi.org/10.1093/nutrit/nuv063
Kerksick, C. M., Arent, S., Schoenfeld, B. J., Stout, J. R., Campbell, B., Wilborn, C. D., ... & Antonio, J. (2017). International Society of Sports Nutrition position stand: nutrient timing. Journal of the international society of sports nutrition, 14(1), 33.
McDermott, B. P., Anderson, S. A., Armstrong, L. E., Casa, D. J., Cheuvront, S. N., Cooper, L., ... & Roberts, W. O. (2017). National athletic trainers' association position statement: fluid replacement for the physically active. Journal of athletic training, 52(9), 877-895.