Something that I have had to come to terms with as I proceed through my thirties is that my body is like a machine. A machine that requires good fuel, consistent maintenance, proper care, and a little bit of love otherwise it will rust to pieces. The fuel and maintenance aspects are becoming increasingly important as I cease to be buoyed by the invincibility of youth. The short version for me is that if I eat like crap and sleep like crap; I feel like crap and run like crap (one more crap for good measure. This article is now rated T). 

While getting good sleep is its own problem set, getting proper fuel is something a little more within the realm of control and as always SCIENCE IS HERE TO HELP! I’ve always kind of played it by ear and gone with the prevailing runner’s cultural wisdom regarding what to eat before and after a workout and when exactly to eat it. But as we know, sometimes runners perpetuate ideas that have little basis in science, and also things that work for one person do not work for all. So I decided to do a little research to see if there was a helping of science to go along with the pre-, post-, and during-workout fueling paradigm. 

The main article that I read is here if you’re curious and I also poked my head into some of their citations to verify information. I’m going to summarize what they found and reiterate their caveats: this is not medical advice, always consult your physician regarding changes. This is a limited study that encompasses a few demographics and thus should not be seen as gospel for all people as many aspects of human physiology can influence the results aka your mileage may vary. Anyway, on with the summary!

Review of: Carbohydrates and Endurance Exercise: A Narrative Review of a Food First Approach (Naderi et al., 2023)

This article looked at the influence that common carbohydrate sources had on aspects of athletic performance when consumed before, during, and after an intense workout. This is a review paper so they aggregated the results from many different sources and thus the studies are not necessarily consistent nor do they encompass the same demographics. It is also important to note that the types of exercise also differed i.e. running vs cycling and the metrics of athletic performance but for the most part, they were concerned with how long a subject could exercise until exhaustion or their comparative performance for the same trial across different sessions. Carbs were categorized also by their glycaemic index (GI) or how quickly they can increase glucose in the bloodstream. Low GI foods are things like pasta, grainy bread, beans, and fruit whereas high GI foods are potatoes, white bread, short grain rice, literal sugar, and sugary foods

Pre-workout 

First off, you don’t really need to carb load that much before a workout, and doing so is really only helpful if you will be working intensely for more than an hour. But for shorter workouts, it is recommended that you get some form of carbs into your body up to 4 hours before the workout. They found that there were some small differences in whether you eat low GI or high GI with high GI foods being better but more so in shorter intensive workouts. Bananas (which are going to appear a lot here) and raisins are fantastic pre-workout foods as they have a good glycaemic balance, usually don’t cause too much gastrointestinal distress, and are demonstrated to be beneficial to performance. If you’re going for the long haul then low GI foods like oats (with bananas) is your best bet because of the aforementioned GI but also because oats also impart hydration over time. What the studies also agree on is that you really should eat something at least an hour before your workout otherwise the feeling of post-workout fatigue is likely to be greater. Don’t run on an empty stomach folks. 

During Workout

This predominantly applies to longer workouts 1-3 hrs otherwise your metabolism simply isn’t fast enough for any impacts to become apparent and also it's working at a different level. This is one of the trickier fueling times because your feasible options are limited by what you can carry or what you can comfortably consume while still needing to move, no one likes running while bloated. The bottom line here is that if you are in an elevated workout state for more than an hour, you need to refuel to maintain your performance and the source matters less as opposed to how full it makes you feel. The winner here again is bananas with the hefty caveat being that they are hard to eat on the go and can make you feel a little fuller than you’d like. Honey can also be a good alternative but is pretty high in fructose so it can cause some stomach discomfort. Basically, here you want a quick punch of glucose and a little bit of fructose so half a banana and some sports drink should set you right. They actually recommend a banana slurry or a banana pureed in water….miss me with that one.

Post Workout

Set yourself up for success my friends! The post-workout carbs are primarily to help your recovery for the next workout and to replenish what you lost. After a workout, your body is like a grocery store frantically trying to restock after the Thanksgiving rush. Except if they don’t have what they need for the next time you workout they kinda just shrug and go “guess we’ll get some of the expired stuff from the back”. The important window to consider here is around 4 hours after your workout as that is when your body is really in restock mode. Studies are mixed on whether you should go with low or high GI foods and it seems to depend on just how long you are resting. If the rest period is short then high GI meals may be better and if longer consider low GI meals. What seems to be most important is the total amount of carbs you get back in you because your goal should be to get back to the glycogen levels you had before you worked out. Also good news! Chocolate milk is scientifically demonstrated to help recovery and is a valid post-exercise meal! CHUG THE MILK (or a non-dairy alternative as long as it has protein, fat, and carbs!). Actually, while we are on the subject, protein is a critical part of the post-recovery meal so having combo sources is ideal. Also as you probably guessed, ya boy banana is appearing again as a good recovery meal BUT NOT BY ITSELF! Get some protein in there. 

In Summary

YOU. NEED. TO. FUEL. YOURSELF! Before, during, and after working out to have a good workout, maintain performance, and prepare for the next one respectively. There are some differences in low vs high GI foods in regards to performance but honestly the studies are too varied to be conclusive about what is best for what stage of the workout and it boils down to the simple fact that you need carbs at every stage and you’d do well to play around with what works well for you and your body. Bananas are the magical exception as they seem to have applicability no matter when you eat them whether that is whole or as a slurry if you are feeling unhinged. What is also important is that your body can only store so much so “loading” on any one particular thing is only going to get you so far which is why carb loading for several days is unnecessary. What is necessary is consuming enough carbs to keep your levels high enough for your body to effectively use when it needs them. Also please note that a lot of this will really only be applicable for longer or intense workouts just by virtue of how your body utilizes energy i.e. don’t carb load for a 5k unless you plan on spending an hour doing it. And it should be said that nothing is wrong with the commercial energy products like Gu or those funky super waffles and some of them may even be slightly better as they can contain other important nutrients for your workout like salts. Lastly, as I mentioned before no study can account for every single aspect that makes a human, there are large base physiological differences between humans that can alter the applicability of any of these results. So test it for yourself, eat a banana before a workout see how you feel!