CrossFit & a Keto Diet – The Perfect Combination?

Both CrossFit and the ketogenic diet are popular health and fitness tools.

CrossFit offers the benefits of stronger muscles, more efficient lungs, and an overall ability to do more work faster than you could before.

Keto promises benefits like weight loss, a boosted metabolism, and can reduce your risk of certain diseases.

So the question is: can CrossFit and a keto diet be combined to form a "superteam?" Or will that not work.

Here's a conclusive answer to help you implement the keto diet effectively into your CrossFit routine. 

Read Also: CrossFit Strength Training Program And Workouts

The Ketogenic Diet Explained

The ketogenic diet is a high-fat, low-carb, moderate protein nutritional approach. 

Like the paleo diet or zone diet, it is most commonly used by people trying to lose weight. But there are certain circumstances where people use the diet to improve performance as well.

The difference between those other diets is that on keto, you purposely deplete your body of glucose by eating between 20 and 50g of carbs per day (in some cases, less). 

After a period of 3 to 10 days (it varies depending on the person), your liver will start producing ketone bodies (also called ketones), which your body then uses for fuel instead of glucose.

Keto Diet explained

Why is this beneficial? Because ketones use your body's natural fat storages instead of muscle glycogen to fuel your body.

Running on ketones effectively turns your body into a fat-burning machine—you use fat to fuel everything you do, from exercising to walking around the office. You even burn fat when you're sleeping.

There are other benefits to going keto, too, which we'll discuss (See section: "Why go keto?" below).

But first, let's review the three principles of a keto diet, and how each section applies specifically to CrossFit.

Eat Lots of Fat

A keto dieter typically gets about 70 percent or more of their calories each day from fat. 

Foods like nuts, healthy oils like coconut and olive oil, other coconut products, and the natural fats found in meats (like fish or beef) help fuel the majority of the diet.

Anyone with experience can tell you that having energy is an essential component of CrossFit. It's very hard to get through a difficult MetCon workout or get through a strength training session with exercises like squats and farmer's walks if you aren't eating enough food—which is why eating plenty of fat on keto is essential.

Read Also: Farmer's Walk - Benefits, and How to Program

Fortunately, fat has more calories per gram than protein or carbs (9 as compared to 4), which can help give your body the clean fuel it needs to perform.

Eat Very Few Carbs

As discussed above, keto dieters eat about 50g of carbs per day at the most. (Although many count net carbs instead of regular carbs, which takes into account things like fiber and sugar alcohols.) This accounts for about 5 percent of their daily calories.

Crossfit Keto Carbs to eat

They do this to induce ketosis, which is a powerful and proven way to lose a lot of excess bodyfat. Some even use intermittent fasting to achieve this effect, as not eating or eating in a timed window can help deplete your body of carbohydrates faster.

Read Also: Intermittent Fasting - The End All, Be All Guide For Beginners

As a CrossFitter, it's probably best to eat the majority of your day's carbs around when you workout. In fact, a half and half approach is probably ideal.

This way, you get about 25g of carbs to fuel your workout efforts, and then get some carbs after your workout to boost recovery. (Studies show eating some carbs and protein after a workout is essential for maximizing your post-workout nutrition.)

The rest of the time you can look for high-fat alternatives to normally carb heavy foods, like this keto sushi recipe.

Eat Some Protein

Keto dieters get the rest of their calories, about 25 percent, from protein. This equates to about 100 to 125g of protein per day (although a bigger person will likely eat more).

If you're a CrossFitter, you probably don't need the importance of protein explained to you.

Protein is a powerful nutrient that helps rebuild muscle. It's also crucial for regulating hormones and for keeping you full longer after meals.

Whether your goal is to lose weight or gain muscle, eating enough protein on keto (or just in general) is essential for getting results.

Why Go Keto?

There are several benefits to going keto, many of which can be applied directly to CrossFit performance and overall health.

Here are some of the most important ones:

Related Read: How to overcome the Keto weight loss plateau

  • Some studies have shown that a high-fat, low-carb diet can greatly reduce or reverse poor metabolic health, which can lower your risk from a whole host of other diseases.

  • The keto diet promotes lots of protein and fiber, two nutrients that help rebuild muscle and promote satiety after meals (essential for weight loss).

  • After an initial adjustment period, many keto dieters say they have more energy from living in ketosis than they did when eating carbs.

Read Also: CrossFit Girls - A Comprehensive 2020 Guide on Benchmark WODs

These benefits are attractive, but the key lies in whether or not going keto works for a CrossFitter. We'll examine that below. 

The Benefits of The Keto Diet for CrossFit Athletes

The major benefit a CrossFiter will receive from going keto is weight loss.

Combining CrossFit with keto can be a very powerful way to lose weight. Not only is ketosis a proven way to shed excess body fat, but the high-intensity nature of many workouts in the sport also promotes a reduction of fat.

You essentially get a "double-whammy" of fat-burning power from combining the two. If weight loss is your top goal, you won't find a more powerful combination.

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The other main benefit is only really applicable to those CrossFitters coming in with preexisting health or metabolic issues. 

Keto can help reduce or reverse the effects of things like type 2 diabetes and generally give you more energy, which can of course be helpful for better performance in the sport.

Read Also: CrossFit Dumbbell Workouts Plus 5 Killer WODs

The Drawbacks of Keto For CrossFit Athletes

However, it's worth pointing out that keto doesn't come without a few drawbacks.

For starters, it takes a while to adjust to eating that much fat (and so few carbs).

Many users report side effects like nausea, dizziness, fatigue, headache, constipation, and most pertinent of all, difficulty exercising when they go keto initially.

Read Also: What is the Keto Flu & cough drops for keto cough

This is an easy explanation—your body is used to running off one fuel source, and now you're switching it to another. There can be a lag time here that may make it hard to do keto and CrossFit simultaneously.

In general, you might need to take it slow and give your body at least 2 weeks to get used to doing both together.

Also, if you're an endurance athlete (or just like long chipper WODs), you may find it hard even after you adjust to complete longer workouts on keto. Your body may simply not have enough energy to perform a hundred kettlebell swings or run several miles. (Although keto supplements like exogenous ketones may help.)

Read Also: Best Keto Fiber Supplements

CrossFit and Keto: Is It The Perfect Combination?

There's a lot to like about pairing CrossFit with the ketogenic diet.

Eating a high-fat, low-carb diet can help you lose a lot of weight and help reduce your risk of many diseases. And because you're eating lots of protein, fibrous veggies, and healthy fats, you'll have plenty of fuel to rebuild muscles and stay full a long time after you eat.

However, there can be an adjustment period that might be challenging to some CrossFitters. You might also find it hard to be in ketosis and complete a long chipper workout like Murph.

The solution we recommend is to adopt a cyclical ketogenic diet. This means eating more carbs (somewhere between 100 and 150g) of carbs one or two days per week, and planning your more difficult workouts on these days.

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The other 5 or 6 days of the week should be devoted to traditional keto, where you eat only about 50g of carbs per day from veggies and low-carb fruits.

That way, you get the best of both worlds—enough energy to crush a killer MetCon, and the metabolic benefits of ketosis to help you shed fat and be healthy.

Ben Kissam

Ben Kissam

I help college athletes maximize their 4-year sports window and succeed after graduation.

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