Preparing for a CrossFit Competition with Nutritional Science

Whether you are preparing for the CrossFit Open, a local CrossFit competition, or another high-level athletic event, it’s incredibly important to train, rest, and eat properly in the days leading up to your event for optimal performance outcomes.

The question is: Which variables are the most important to manipulate to maximize your performance?

The Main Factors

The first and most obvious variable to consider when preparing for a CrossFit competition is your diet. Fortunately, our RP Diet App can take care of that for you, building a personalized plan, adjusting it as needed, and optimizing your performance. 

But, once you’ve mastered the basics of an evidence-based diet for optimal athletic performance, is that all you can do to prepare for your event?
Or, are there other, more specific details to consider when tweaking your lifestyle in preparation for your competition?

Although an optimized dietary strategy is certainly one of the most effective ways to ensure a high level of achievement, there are a handful of other important alterations that can be made to enhance your performance as well.

The key is to make sure that you are already on track with a fundamentally sound diet before making these supplemental changes. After all, if you put low-quality fuel in a Formula 1 car, it won’t matter how skilled your driver is or how perfect your tires are. The quality of the fuel is by far the most important consideration.
But, assuming you’ve thought meaningfully about the basic nature of your diet, let’s move on to a few more advanced considerations.

Eat More Carbohydrates the Day Before

Simply put, you can boost your performance by increasing your levels of stored muscle glycogen. In other words, eat more carbohydrates.

The effects of increasing your carbohydrate intake can be most specifically observed in the number of reps you can perform at a given time. Sounds pretty relevant to something like CrossFit, doesn’t it?

By eating more carbohydrates the day before the workout (or series of workouts) during which you want to perform your best, you fill up your muscle glycogen stores and leave them ready to support your intensified training efforts the next day.

How can you go about this specifically? A good general guide is to eat around 1.5x the average amount of carbs you have per day on the day before your training. Now, that’s the average across all your days, including training and rest days.

So, if you eat about 200 g of carbohydrates on an average day, you’d eat 300 g of carbohydrates the day before your big competition. If you eat 500 g of carbohydrates on a typical training day, you’d want to consume 750 g of carbohydrates the day before your event.

Practically speaking, if you eat four times per day, you could simply add 25 g (or 62.5 g) of carbohydrates to each meal in order to hit your pre-contest target. A few extra oats for breakfast, a bit more rice for lunch, an extra banana in the post-workout smoothie, and a strategic addition of kids' cereal before bed, and you’re well on your way to a well-designed day-before-the-competition dietary approach.

Remember, however, that you don’t have to spread those extra carbohydrates evenly throughout the day. If you prefer eating most of your food in the evening, you could easily consume most of your extra food in the pre-bedtime window. Doing so could promote even higher-quality sleep in particular athletes and aid in added levels of pre-competition recovery. In some cases, this could even mean smashing a few bagels with jelly as an epic nighttime snack.

That being said, a major consideration before diving headfirst into an ocean of kids' cereal is how this interacts with your current diet goals. Are you currently in a massing phase? Are you eating at maintenance? Or are you currently in a deficit?

For example, if you’re actively massing, no consideration is required. You can scarf down those extra carbohydrates with little to no thought of how they will affect your current dieting phase.

If you’re maintaining, you might need to eat a bit more strictly for a day or two later in the week post-competition to get your weight back to normal. But this is totally doable and nothing to be concerned about in most cases.

But, if you’re in a fat loss phase, most athletes would be wise to consider the tradeoffs.

On the one hand, eating 150% of your average daily carbohydrates will stall your fat loss efforts for that day. From an evidence-based perspective, we have to acknowledge that fundamental reality.

But is it really the end of the world to pause your fat loss efforts for 24 hours to perform your best in organized competition? Probably not. Will your fat loss resume normally right after? Absolutely. Will you add fat doing this? Almost certainly not.

But if you don’t want anything to affect your diet progression, and losing fat is of greater priority to you than performing optimally in your competition, then eating something like 125% or even just 100% of your average daily carbohydrates could be a more appropriate and less obstructive strategy in this case. It all depends on your individual priorities.

In any case, the idea is to make the tradeoff that best supports the most relevant combination of your short and long-term goals.

Eat More Carbohydrates the Meal Before

If eating more carbohydrates for an entire day before a workout seems a bit excessive in your situation, you could choose to eat just 1.5x the normal amount of carbohydrates in your pre-workout meal.

Practically speaking, this is essentially the difference between giving your body every opportunity to perform maximally versus giving your body almost every opportunity to perform maximally.

At the same time, there’s no way to observe yourself in a parallel universe eating a 1.0 multiplier versus a 1.5 multiplier to understand the added degree of benefit truly.

Because of that, this choice should probably be considered most by those on fat loss plans that don’t want to navigate the fat loss delay of an entire day of carbohydrate consumption. If you don’t want to waste any time out of a deficit, you don’t have to.

Conversely, if performance is absolutely your number one goal and your acute weight is not of concern to you, it could be a good idea to consume a large amount of carbohydrates in your day-of pre-workout meal and bolster your carbohydrate consumption to 150% the day before.

When optimal performance is on the line, the last thing you want to risk is being slightly under-fueled. Again, the key is determining what is most appropriate for your situation and acting accordingly.

Be Mindful of Your Hydration and Salt Intake

When eating more carbohydrates than usual, hydration, salt intake, and electrolyte balance can also become problematic if not carefully monitored. Specifically, one risk here is experiencing unwanted bloat from the extra carbohydrate intake, which could limit your performance in your events. This could be especially limiting in the context of gymnastics and endurance-based events, which is obviously counterproductive given that more than 50% of the sport consists of movements that appeal to these two essential categories.

The workaround for this, however, isn’t to reduce the intensity of your carb-up. Instead, the better idea is to keep your salt intake in check, which begs the question: How much salt should you be consuming on the day of your competition?

Interestingly, most experts agree there isn’t a one-size-fits-all recommendation for salt intake.

Unlike protein or carb consumption, appropriate salt intake from athlete to athlete can vary wildly based on a host of variables, including temperature of the exercise environment, exercise type, exercise duration, clothing type, and even genetics in the realm of sweat ion concentration.

For some, 1,000 to 1,500 mg of sodium may be ideal, while, for others, 10,000 mg still may not be enough on a very long, hot endurance-training day. It’s also important to remember that needs vary daily based on unique circumstances, making any single recommendation nearly impossible to issue.

The good news is that it’s very unlikely that you’ll overdo it with your salt intake as a CrossFit athlete. Sure, there are exceptions, but research shows that only people with high blood pressure need to worry about limiting their salt intake.

At worst, your kidneys will “clean house” and excrete excess sodium in overconsumption cases, especially among healthy populations.

Additionally, one of the benefits of being a CrossFitter is that there are no weigh-ins to fear for weight class requirements. In other competitive sports like weightlifting and powerlifting, excess salt intake can cause the scale to tip the wrong way at precisely the wrong moment.

Eating up to 150% of your carbohydrate intake without unwanted additional salt rarely results in a performance-dampening bloat.

So, what’s the best way to keep your salt in check?

Supplement your diet with healthy carbohydrates like rice, pasta, potatoes, or fruit instead of heading straight for higher-sodium sources like potato chips or other highly processed foods. This will give you the best chance of mitigating any unnecessary bloat.

Another important consideration is your electrolyte balance.

And really, there’s no need to make it any more complicated than that.

In terms of good practices for general hydration, all you need to do is make sure your urine is clear or light yellow and of relatively high volume at most times. If you can combine these hydration habits with proper salt intake on the day of your competition, you’ll be in a great position to perform your best.

Focus on Proper Recovery Practices

Although this isn’t explicitly a diet tip, it’s important enough that we felt it deserved an honorable mention. In short, don’t let an obsession with optimizing your diet negatively impact the tried and true recovery protocols we’ve known to be beneficial for athletic performance for decades.

For example, plenty of sleep and a low-stress attitude contribute powerfully to lowering your fatigue and letting your fitness express itself in a high-performance setting. Make sure to do everything in your mental power to keep yourself as calm and relaxed as possible in the days leading up to your competition.

Although a certain degree of external stress may be unavoidable due to the adversity of competition, you can always control how you respond to those external stressors. Put simply, do your best to keep cool and save your internal angst for the competition.

In the nights before (and especially the night just before) your competition, monitor your sleep and be sure to get plenty of it.

In most cases, between 7-9 hours will be sufficient for most people, but what you need is what you feel you need. If you can wake up for the workout day with clear eyes and abundant energy, you likely get plenty of sleep.

But, if you’re prone to groggy on reduced quality and quantity of sleep, you would be wise to be extra mindful of your sleeping patterns the week before your event.


The best thing you can do to prepare yourself for a competition in the realms of CrossFit, weightlifting, or powerlifting is to master the basics of proper nutrition for athletic performance, which, once again, with a shameless plug, our RP Diet App is close to magic. 

Once you’ve done that, you’d be smart to increase your carbohydrate intake the day before your event and for the meal directly before your event on the day of the competition.

Beyond that, monitoring your hydration and recovery is extremely important as well.

And finally, have fun! It’s a privilege to compete in a sport you love, so do your best and enjoy the process from start to finish. The entire RP team is rooting for you!

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