The Crossfit Diet: What It Is, Risks and More

Most are probably familiar with the cult-like appeal of CrossFit, the wildly popular exercise regime that takes place at a special type of gym, which is referred to as a “box.” There, participants follow a group workout of the day, or “WOD,” consisting of high intensity cardio and lifting.

Because nutrition is an essential part of performance, following a healthy and high protein diet is crucial. The CrossFit diet aims to provide its athletes with enough carbs to stay energized, and protein to stay lean.

CrossFit Dieters Track Their Macronutrients to Stay Fit

The CrossFit diet is a low-carbohydrate, high-lean-protein diet that involves tracking macronutrients. The program has a mantra for what to eat while CrossFit training: “Eat meat and vegetables, nuts and seeds, some fruit, little starch and no sugar. Keep intake to levels that will support exercise but not body fat.”

A typical meal, according to Healthline, would include: one-third lean protein, two-thirds healthy starches (low carb vegetables), and a small amount of healthy fat. This almost entirely based on the Zone diet, which was created by biochemist and author Barry Sears, and his fad diet book, The Zone.

Building Muscle Is the Primary Goal

Woman’s World spoke with Vicki Koenig, MS, RD, CDN, of Nutrition Wise about the benefits of the diet. She says its allure stems from the high protein requirement, which helps build muscle.

“The benefit of following the CrossFit diet is that it’s balanced in the macros. This means it’s a good balance of protein, carbohydrate and fat,” she explains. “With an emphasis on good lean proteins balanced with less refined carbohydrates, CrossFit athletes are less hungry. This also helps build muscle and lose body fat.”

Cutting Carbs Helps Dieters Maintain a Lean Physique

The diet, per the National Library of Medicine, supposedly offers enough carbohydrates to complete a CrossFit workout. However, it does not provide enough for them to store any additional fat. It also offers a surplus of protein to build muscle. Macronutrient intake would include 40 percent carbohydrates such as low-starch vegetables, 30 percent lean proteins and 30 percent fats.  

“Following this diet will help nourish the body with high quality foods that support muscle-building and replenish energy used from glycogen (our body’s stored carbohydrates),” Koenig explains. “The CrossFit diet recommends that the diet consist of 40 percent carbohydrates, 30 percent protein and 30 percent fat… This diet composition is not the same as what the International Society of Sports Nutrition recommends.”

The CrossFit Diet Is Similar to Keto, Though It’s Less Rigid

The high protein and fat intake makes the CrossFit diet and keto diet look similar. However, Chrissy Barth, MS, RDN of Epic Biology in Phoenix, Ariz. points out one key difference.

“While the CrossFit diet shares similarities with the ketogenic diet in its low-carbohydrate approach and emphasis on fats and proteins, it is not as rigidly structured,” she explains. “It allows for more flexibility to accommodate the needs of athletes for example engaged in high-intensity training by incorporating additional carbohydrate sources such as fruit and starchy veggies like sweet potatoes, beets and winter squash.”

Related: The Keto Diet Explained: Is the Popular Weight Loss Regimen Effective?

The CrossFit Diet Makes Some Feel Energized, While Others May Have Unpleasant Symptoms

Those who are partaking in CrossFit without a proper diet, according to training site The Progrm, can experience fatigue, excessive muscle soreness and a lack of results with the workouts. However, the thought is that with the right caloric and protein intake, that wouldn’t be the case.

With most low-carb, high protein diets, many report feeling energized and focused; however, some have also reported digestion issues, moodiness, dizziness and fatigue associated with lowered carbohydrate intake. Barth explains the side effects can vary from person to person:

A diet that might work for someone may not for someone else…. When it comes to nutrition, personalization is key. Additional variations in how individuals respond to the CrossFit diet can be attributed to several other factors including metabolic differences, the adaptation period of following a new diet, carbohydrate sensitivity, diet quality and hydration and electrolyte needs.

Chrissy Barth

Results of the CrossFit Diet Are Similar to Keto

According to Protein Chefs, the CrossFit diet can lower insulin levels in blood and stave off hunger. It can also reduce inflammation, which can — in turn — boost recovery for workouts, which is a major plus while training.

Some nutritionists, however, don’t believe sticking to such a restrictive diet long-term is achievable.

There May Be Long-Term Risks Associated With the Diet

Dieters are at risk for multiple deficiencies, because it’s a relatively restrictive diet. Because low dairy intake is recommended, for example, it may result in a calcium deficiency, according to Boston Specialists Food restrictions also may result in a deficit of Vitamin C, and B, folate, and fiber.

Because the diet is also high in fat and protein, those at risk of kidney disease and high blood pressure also aren’t advised to follow it: “Concerns about high-fat and high-protein diets regarding kidney disease and high blood pressure stem from several factors,” Barth explains.

High protein intake strains the kidneys as they need to work harder to metabolize and eliminate protein byproducts, especially challenging for those with kidney issues.

“High-fat diets, particularly rich in saturated and trans fats, are linked to hypertension due to arterial stiffness and inflammation,” she adds. “Additionally, diets high in ultra-processed foods often contain excess sodium, promoting water retention and increasing blood volume, thus exacerbating hypertension, a risk factor for kidney disease and cardiovascular conditions.”

Not All Fats and Proteins Are Created Equal

Barth adds healthy fats are extremely beneficial. So this isn’t always true.

“Healthy fats, such as those found in avocados, nuts, seeds, and fatty fish, can have beneficial effects on cardiovascular health when consumed in moderation. Similarly, lean protein sources like poultry, fish, legumes and tofu are less likely to exert excessive strain on the kidneys compared to high-fat or processed protein sources,” she notes.

In addition, individual factors such as genetics, diet quality, lifestyle habits, and pre-existing health conditions play a significant role in determining how dietary fats and proteins impact kidney health and blood pressure.

Chrissy Barth

Budgeting Requires Extra Effort — But There Are Ways to Save

Similar to the keto diet or any other diet that negates carbohydrates, a typical grocery haul might be more expensive than usual. But to save money while following the CrossFit or Zone diet, U.S. News recommends opting for seasonal produce, canned or frozen when available, buying in bulk, opting for protein when it’s on sale, and using discounted Zone products online. However, as a rule of thumb, choosing non-packaged food items is generally cheaper.

“Getting enough protein can be expensive. When you’re emphasizing turkey breast versus chips or even fruit, it’s costs more,” Vicki Koenig explains. “Tips for saving a bit on vegetables can be to buy them frozen and add them into dishes. Sometimes a protein powder made into a smoothie can be helpful to save time on breakfast or other food prep or eating out. This can also reduce the cost of the protein addition in the diet.

Vicki Koenig

Vegans and Vegetarians Will Need to Load up on Protein

“The focus would be on getting enough protein from vegetarian sources,” Vicki tells us. “A vegan CrossFit Diet, of course would also eliminate any lean dairy or eggs. This would require focusing on tofu, tempeh and legumes.”

Additionally, plant-based protein powders like pea, hemp, and soy protein can help to boost the protein. Someone who has allergies to any of the common allergens are already dealing with potential limits on types of proteins available in the diet like milk, eggs, fish, shellfish, tree nuts, peanuts and soybeans. These limits do add additional challenges.

Vicki Koenig

The CrossFit Diet Can Be Easy — It Just Requires Preparation

Like other low-carbohydrate diets, following the CrossFit or Zone diet requires quite a bit of planning and meal prep. Dieters may not feel the “freedom” to eat out at all the restaurants they’re accustomed to going to, or out to the bars, because of the “meats, veggies, fruits and seeds” requirement.

But those who are willing to make that sacrifice, and who can prepare some grilled chicken salads to have on hand during a hunger emergency, are more than capable of doing it. While there may be a few unpleasant symptoms that come with it, it ultimately seems like a safe lifestyle (at least for a little while) while CrossFit training. 

“The CrossFit diet requires planning,” Koenig reiterates. “It’s not impossible to follow when eating out, but it’s better to bring it with you.”

It can also be challenging if eating at an event. While many family and friends’ events focus on carbs like pasta, bread and sweets, this diet excludes those! The key is planning ahead so you have good choices.

The CrossFit Diet Can Be a Sustainable Path to a Lean Body

Although the CrossFit diet may not be for everyone, it doesn’t pose a huge risk to your body — and it could even have benefits to those partaking in the high intensity workouts. Like any diet, it requires quite a bit of meal prep and planning, but as long as you take the steps you need to adhere to the diet correctly, you may see the weight loss results you’re looking for.