Fueling For Fitness

Let food be thy medicine, and medicine be thy food” 

When it comes to fueling for fitness, I encourage my clients to test, never guess. Yes, initially it will require some trial and error, wished you had packed some TP for that long run anyone? But when it comes to specific exercise modalities each effort requires specific fueling needs. Wondering how a weightlifting session might differ from a long run? Read on.


When talking about an aerobic/endurance effort it’s important to make sure you are in the zone you think you are in. When I say aerobic, I’m talking about the Sunday morning long run or the 2-hour bike ride with friends.

A great way to judge if you are in the aerobic zone is to ask yourself, can I sing a couple of lines to a song before running out of air? Aerobic after all means, “with oxygen” during these efforts think and plan towards a steady ingestion of carbohydrates. Recent literature suggests that every 20-30 minutes an athlete can plan to be ingesting 20-30 grams of carbs [1]. Aim for a 2:1 blend of Maltodextrin and Fructose. New research is emerging on this topic and some reports indicate the gut can handle up to 100g of carbs an hour[2]! The gut is after all a muscle like just your heart or legs, you just have to train it.

Anaerobic/Sprint Session

In these high intensity sessions we are “without oxygen” for the effort. As a result, the body is using carbs to fuel the effort at a much quicker rate. Thus, it’s advised that consumption of carbohydrates 90-120 minutes prior to the workout will ensure that your glycogen stores are topped off and prepared to fuel you. Think bagel, think oatmeal, think banana, think dates. Again, you’ll need to test these in training as all of the foods I listed have varying amounts of fiber which is known to cause GI distress for some individuals, we are all different.

When training in the anaerobic or lactate threshold zone, workouts usually call for long periods of rest to allow the body time to buffer lactate out of the muscle and fully recover. During these periods (2-6 minutes) while you are catching your breath and wondering why your lungs are on fire, take a sip of a carbohydrate drink (same mixture as I shared above) and get ready for the next effort. Post anaerobic session you may find that you are not as hungry as you would expect.

A study from 2017 showed that the hunger hormone, Ghrelin was reduced following harder effort workouts[3]. Keep yourself hydrated and continue to sip on some carbs. Once hunger does return be sure to refuel properly over the next 24-48 hours as it can take this long for complete muscle glycogen refuel.

Maximal Strength Training

When pushing heavy weight around its vital that you are fueled before, during and after the session. Again, a snack is your friend in the lead up to the session. I recommend 200-300 calories 90-120 minutes prior. During the session, carbs will fuel your performance. Think 20-40g depending on your bodyweight and session length(anything over an hour you’ll need more). Immediately post workout(30-90 minutes) aim to get 2:1 carbs to protein via liquid or food to help with protein synthesis[4]. This could be a banana and peanut butter, or it could be a glass of chocolate alternative-milk (my personal beverage of choice).


Perhaps you have an “easy day” on the schedule, or a light lift planned that is not going to require big effort and fueling. On these days, if working out in the morning, I encourage you to try the workout fasted. It’s a great opportunity to use fat as fuel, something you’ll need your body to be able to do if you participate in endurance events and it’s also a great way to help the body and brain learn how to play “low” on carbs.

Once the workout is over and during the remainder of the day, I encourage you to make sure you are taking in quality calories from a variety of whole food sources. I’ve had clients before call rest days, “cheat days”. I get the reward thinking, but from a performance standpoint your body will thank you if you choose to pick lots of fruits, vegetables and lean protein sources to help do what your goal is for the day, recovery. 



[1] Menzies, C., et al. (2020). "Frequent carbohydrate ingestion reduces muscle glycogen depletion and postpones fatigue relative to a single bolus." International Journal of Sport Nutrition and Exercise Metabolism 30(1): 25-33.

[2] Jeukendrup, A. E. (2017). "Training the gut for athletes." Sports Medicine 47(Suppl. 1): 101-110.

[3] Islam, H., et al. (2017). "Potential involvement of lactate and interleukin-6 in the appetite-regulatory hormonal response to an acute exercise bout." J Appl Physiol (1985) 123(3): 614-623.

[4] Knuiman, P., et al. (2015). "Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise." Nutrition & Metabolism 12(1): 59


About the Author

Rob (Hardin) Anderson is a nationally certified Personal Trainer, Group Fitness Instructor and Nutrition Coach. He is currently pursuing a M.S. in Nutrition & Food Systems at the University of Kentucky. His research focuses on exercise, food behavior, weight loss and how the three intersect. When he’s not coaching a client or working on research you can find him pushing his body and brain to the limits training for a Marathon or Spartan Race. You can follow him on social media @RobertHardin or learn more about him at his website, robhardinfitness.com.