Being in great shape and being in race shape go hand in hand—or do they? As we prepare for Spartan races we always want to be our best, but that means different things to all racers. Our goal is to tackle the course and be successful, whether that means finishing, competing for time, not getting injured, or not doing burpees. No matter what your goal, staying in “race shape” before, during, and after a race is extremely important, and the biggest factor beyond physical training is nutrition. You need to be hydrated and fueled correctly to tackle long races, especially when you consider an ultra distance like an Ultra Beast, which could be up to 30 miles.

Racers want to be lean, mean, and strong going in to the race, but what if doing so puts you at risk during the race? How you fuel yourself plays a large role in achieving fitness, being race ready, and building lean muscle for strength. These days many athletes are gravitating to ketogenic diets, intermittent fasting, and carb-loading. Can you follow a path of intermittent fasting and still be race ready? Yes you can, and here’s how.

First, for those who are new to the topic, intermittent fasting means taking periodic breaks from eating to allow the body to break down excess fat. Intermittent fasting seems to dispel a few theories as well as strengthen known facts—here are a few to consider:

1. Eating small meals all day doesn’t necessarily speed up your metabolism.
2. Eating a ton of carbs is just that. Yes, you can carb-load for racing, but doing this all the time just means your body will not burn off excess fat; it will just burn the tons of carbs. Excess protein becomes fat as well (bad cycle to be in).
3. Ketogenic or high-fat diets (lowering carb intake) will still give you energy, but the carbs are not loading up and possibly making it harder for your body to burn fat.
4. Giving your body time to burn off that fat by fasting will allow you to get leaner.
5. Carbs seem to provide for a better energy source for endurance racing, as they burn fast when you need energy most.

So much to think about when all you want to do is look great, feel great, and race great. How do we balance all of this out? Listen to your own body—that’s how. You have to consider what your body needs when you are going to race and make sure it is fueled correctly. For example, it would not make sense to do a long fast leading into a race where you will need calories to burn. Let’s say you planned to do a Spartan Beast (13+ miles) on a Saturday. In that case, you can fast early in the week and start to load up at the end of the week to prepare for the race. Make sure you go into the race well hydrated and with the carbs you will need to race with. Do not starve yourself! Yes, as you adjust to this type of diet, you will experience hunger. It will subside over time as you get use to the plan, but this is very different than depriving your body of what is needed to survive. You definitely do not want to be depleted leading into a race.

Another option, if you feel weak leading into and during a race, is to do your periods of fasting in the off-season. Also make sure you take your post-race nutrition seriously. After a race, your body will need to recover, so fasting directly after a race is not recommended. It makes more sense to replenish the nutrients your body needs, especially protein, after the race. Then, once you finish the race and are recovered, you can go back to your regimen of intermittent fasting in between race cycles.

Will this work for everyone? Obviously, everyone is different, and some people find that working out during a fast works for them. This is why you need to listen to your body, learn what works best for you, and only use guidelines such as this as a general rule of thumb. One thing we can all agree on is never go into race day with a new plan that you have not tested first. You should go into race day having trained (and fueled) so you know what works, because once you add the weather, the obstacles, and the rough terrain, you will not want to be at an energy deficit. Test your system first and make sure it works.

Important takeaways—intermittent fasting is just that. By skipping a meal here and there, you can gain the benefits such as reduced inflammation in the body and the burning of excess fat; however—it is just that: intermittent. As an athlete, you need to be careful with depleting yourself of needed nutrients when engaging in endurance activities—especially a Spartan race where your body will be tested thoroughly.

This article is not telling you how to fast. It is telling you that if you are interested in doing so or already doing so, how to navigate the racing with it. You should always consult a registered dietitian or licensed nutritionist with any dietary needs or questions regarding your health.

The right food is the most powerful health drug of all. Download a free Spartan Meal Plan.