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Pre-workout: To eat or not to eat?




One of the greatest challenges for an endurance athlete is translating the fitness gained in training into a great race day result. Interestingly, far too many athletes don't compete based on repeated training-related decisions. As an example, many (if not most) athletes tend to underfuel in training and overfuel before and during race day. To feel confident for race day, you need to feel confident with your training-related nutrition decisions. Therefore, train like you want to compete.

It seems obvious that if you want to excel on race day, you should make repeated decisions in training that help you prepare for your upcoming race. Rushed and busy schedules, poor planning, misguidance from social media "experts", a complicated relationship with food and the body and unhealthy lifestyle habits make it easy to check off workouts without making significant gains in performance. Unfortunately, athletic success doesn't occur when you are a dedicated exerciser who just checks off workouts. You must give 100% into your training, which means focusing on any and every aspect that will help your body better adapt (and recover) from training stress.

Because different nutritional training methods can be used to obtain specific goals, I'm not here to tell you that you have to eat before your workout. However, I feel it's essential to focus on every way possible to achieve a high level of quality training to optimize long-term training adaptations and overall health. Despite clear benefits of pre-workout carbohydrate ingestion on improved performance, mental focus, immune system health and longevity in sport, athletes still refuse to intentionally not eat before early morning workouts. Here are the most common reasons why:
  1. I need to burn fat for fuel - In my opinion, this is the number one reason why athletes intentionally restrict/avoid consuming carbohydrates before an early morning workout. The primary science behind fasting relates to its metabolic effects - by working out on an empty stomach, fat burning is enhanced. Although there are several different approaches to manipulate the diet in an effort to train the muscles to more readily use fat as a substrate, let's put science aside for a second and look beyond a cellular level. As an athlete, your training is designed to prepare you for your upcoming event - not prepare you for a weight loss competition. Will a small difference in your body fat percentage make a significant difference in your race day performance? Additionally, training yourself to become a great fat burner doesn't always equate to being a great athlete on race day for so many factors affect your race day performance. It's unlikely that your body fat percentage or fat burning capabilities are your primary limiter for why you are unable to perform to your potential on race day. As you balance work, family/kids, training and a busy life, you must ask yourself if optimizing fat oxidation by not eating before an early morning workout is making a substantial difference in your athletic development? Keeping in mind that most athletes nullify the effects of a fasted workout by being sedentary throughout the day, skipping meals (or overeating) and skimping on restful sleep, I feel it's better to fuel to perform a quality training session. If you aren't putting effort into your sleep, eating, hydration and recovery habits, the occasional or regular fasted training session could be hurting your performance, more than it's helping.
  2. I feel nauseous and lightheaded when I eat before a workout - Whereas not eating before an early morning workout may cause a drop in blood sugar (due to low liver glycogen stores), eating carbohydrates in the hour before exercise can cause reactive (or rebound) hypoglycemia. I actually suffer from this and will often get a bit lightheaded in the 15-20 minutes before/during my workout. However, it always goes away and has no impact on my performance. Symptoms include weakness, nausea and dizziness in the first 20 minutes of exercise. Certainly one would think these symptoms would have a negative impact on performance but that's not always the case. Interestingly, some athletes are more sensitive to carbohydrate feedings than others and some athletes are more sensitive to even the slightest drop in blood sugar than others so the key is understanding your body and what works best for your body. Not eating is not the only solution. If you suffer from reactive hypoglycemia, the solution is not to skip the pre-workout meal as you need to figure out the best way to fuel for your longer sessions and upcoming events. A better strategy is to figure out what, how much and when to eat. I suggest to choose lower glycemic carbohydrates that elicit less of a glycemic response and to combine with a little fat and protein to help slow down digestion in the 90 minutes before exercise. You can also try sipping on a sport drink in the 30 minutes before exercise (continue to sip periodically throughout the first 5-20 minutes of training). Because the symptoms of low blood sugar can often be confused with low blood pressure, it's important for athletes (especially female athletes when menstruating) to focus on pre workout sodium and fluid intake as well as rehydration strategies post workout.
  3. I don't have enough time to eat before a morning workout or I have no appetite to eat so early in the morning - This makes sense. If an athlete is waking up at 4am and working out at 430am, is there even enough time to digest a meal? Should you force yourself to eat even if you aren't hungry? The answer to this question goes back to the beginning of this blog - setting yourself up for quality training sessions. If you are an athlete who wakes up at 4am for a workout, your first focus is on getting enough sleep prior to the workout to ensure an upcoming quality training session. Seven to eight restful hours of sleep is encouraged for athletes so if you are falling asleep by 8pm and can sleep restfully through the night, my advice is to push back the workout by 15 minutes to allow a good 30-45 minutes to digest a pre workout snack of 100-200 calories before a one+ hour workout. If the workout is only 30-60 minutes, you can simply sip on a 100ish calorie sport drink in the 5-10 minutes before the workout and continue to sip throughout the training session to offset depleted liver glycogen stores from the overnight fast. If you struggle to eat before a workout due to no appetite, it's worth exploring your eating patterns/choices throughout the day (and through the late evening). Ideally, you want to train yourself not to overeat in the evening so you can wake-up feeling somewhat empty in the stomach. The body's normal digestive rhythm can be trained (so can the appetite). Once again, not eating will not sure a quality training session, especially if the workout is intense or of high duration. And don't get me started on the sleep deprived athlete who sacrifices sleep in order to train....
  4. My stomach gets upset if I eat before a morning workout - Just like you train your muscles, the gut needs time to be trained. Some athletes can eat a big meal in the 20 minutes before a workout whereas other athletes feel uncomfortable by the thought of food in the belly before a workout. First off, it's important to focus on your inner dialogue and the thoughts that may be stressing you out when it comes to eating before a workout. "I feel fat, I don't like food in my belly, I need to lose weight..." can actually increase the risk for digestive distress. It's important to develop a healthy relationship with food and see food as a way to enhance your performance and health. Food is not the enemy. Not eating before a workout doesn't make you a fitter, stronger, healthier or faster athlete. It's ok to feel food in your belly before a workout.
    If you are suffering from a more serious issue such as loose stools, nausea, diarrhea, etc. a slow, step-by-step process is needed. First off, avoid high fiber/fat foods in the 6-8 hours before you go to sleep the night before an early morning workout. Secondly, make sure you are well hydrated during the day and consuming adequate fiber consumption in the daily diet to promote healthy and regular bowel movements. Next, I suggest to start training your gut by consuming a very small portion of a low residue food, like saltine crackers, applesauce or a rice cake in the 30-45 minutes before a very easy workout. As you build up a tolerance, try these foods before more intense sessions. Then, work your way up with more calories and try out different food options. Lastly, you need to train your bowels so that you can go to the bathroom before you workout, which may require that you eating standing up, move around before you start your workout, drinking something hot/warm before your workout or planning a pit stop in the first 10-15 minutes of your workout. Overtime, your digestive system should become more regular so that you are not compromised by digestive issues during your training session. Constipation, stress, poor sleep, a nutrient-poor diet and traveling through multiple time zones can through off you bowel movements so be mindful of how your body is impacted by your day-to-day lifestyle habits. 
For more information on nutrient timing, I dedicated three (very detailed) chapters to this topic in my book Essential Sports Nutrition.