The Best CrossFit Diet: The Zone Diet

Regular exercise should go hand in hand with a well-balanced diet. What about CrossFit, though? Do we have to eat a special diet if we do CrossFit? These are common questions among people who are considering these types of workouts. In this post, you can read the answers to these questions and find out more about the best diet for CrossFit.

Does Diet Matter in CrossFit?

A common misconception is that a strenuous workout eliminates the need for diet changes. If you work out regularly and your routines are vigorous, is it really necessary to watch what you eat? Actually, it is even if you do CrossFit.

In fact, CrossFit is a lifestyle, not just a workout routine. Founded in 2000, CrossFit is a type of lifestyle characterized by safe and effective exercise combined with sound nutrition. This form of high-intensity interval training (HIIT) can be used to lose weight, improve performance, and promote good health and wellbeing (1). In other words, you can use CrossFit to achieve your body goals. To achieve these goals you need to do more than regular exercise. Diet evaluation is crucial.

CrossFit website explains that failing to address nutrition would be like rowing with one oar in the water. You shouldn’t strive to out-exercise a bad diet, because it doesn’t work that way. Exercise and a healthy diet complement one another, they go hand in hand. To get the most from CrossFit you need to work out regularly and optimize your nutrition (2). That way, your body gets everything it needs to help you achieve your goals.

The Best Diet for CrossFit

In order to do CrossFit the right way, you need to assess your diet first. For instance, it’s useful to have a food journal where you’ll write down everything you eat and drink to identify strengths and weaknesses to correct. Only when you have full insight into current eating habits will you know the importance of modifying your diet for the best CrossFit results.

Ideally, your diet should consist of a lot of meat, vegetables, some fruit, nuts and seeds. Also, you should consume a little starch and avoid sugar as much as you can. CrossFit recommends everyone to follow Zone Diet for four weeks to establish measurable, observable, and repeatable data on food intake and athletic performance.

What is a Zone Diet?

As seen above, CrossFit recommends Zone Diet as the best dietary approach for persons who want to start this lifestyle. But, what is it?

Zone Diet, or The Zone, is an eating regimen that focuses primarily on low consumption of carbohydrates. The diet was created by Dr. Barry Seals over 30 years ago. Dr. Seals is an American biochemist and author who spent over 40 years researching how our diet influences hormones and gene expression. The Zone was created as a diet to decrease inflammation and is dubbed effective for helping people slim down and improve mental and physical performance. In a nutshell, the Zone Diet was developed as a long-term eating plan that helps us have a more fulfilling life (3).

How Does Zone Diet Work?

Let’s start with the Zone itself first. The Zone is defined as a real physiological state in the body that can be measured via clinical testing. You’re considered to be in the Zone if you can successfully control diet-induced inflammation. This is important because inflammation is considered the main cause of weight gain, fast aging, and illnesses by advocates of the Zone diet.

To achieve this optimal state i.e. the Zone, it is necessary to consume specific amounts of different nutrients. For example, protein should account for 30% or 1/3 of your plate, carbohydrates 40% or 2/3s, and fat 30% as well. Not all fat is recommended, though. You need to consume monounsaturated fats such as olive oil, avocado, and almonds.

The Zone Diet works through the careful selection of foods you consume. For example, you can’t eat just about any carbohydrate source. Instead, you should opt for carbs with a low glycemic index meaning they provide a slow release of sugar into your bloodstream thereby keeping you satiated for longer. Sources of protein should be lean.

Is the Zone Diet Effective?

Zone diet is a popular choice for many people, especially for those who want to slim down. As seen above, CrossFit recommends it as the best diet for persons who want to do their HIIT workouts. Is the Zone Diet effective, though? While studies on this subject are relatively scarce, current evidence shows it could be effective for weight loss.

One study involved 30 obese and overweight women who were randomized to the Zone Diet for six months. After the study period, subjects who followed this diet lost 7.4% (6.9kg) of weight on average compared to their baseline weight. In a different study, 40 participants were randomized to the Zone Diet and the average weight loss after six months was 3.4% (3.4kg) of their baseline weight. The mean weight loss after 12 months was 3.2% (3.2kg). It is also important to mention research of 79 overweight and obese premenopausal subjects showed an average weight loss of 2.4% (2kg) after six months. In his study, weight loss after 12 months was 1.8% (1.5kg) of baseline weight on average (4567).

While the above-mentioned results are moderate, they do show Zone Diet could be helpful for persons who want to slim down. A lot more evidence is necessary to get a full insight into the weight-loss potential of The Zone Diet.

When it comes to athletic performance, current evidence shows the Zone Diet may not be that effective as it’s claimed (8). However, a study from the International Journal of Exercise Science found consumption of low-glycemic carbs, as recommended by the Zone Diet, could increase glucose stores in muscles. These stores fuel your athletic performance. While the effects are short-term, the results did show the positive impact of this diet on physical performance (9).

The entire mechanism of action through which the Zone Diet influences athletic performance is unclear, though. The biggest reason is the scarcity of studies. Plus, studies that evaluated this aspect of the Zone Diet enrolled endurance athletes, not necessarily CrossFitters.

Benefits of the Zone Diet could go beyond weight loss and improved athletic performance and extend to other aspects of health and wellbeing. Carbohydrate-related guidelines could be beneficial for the prevention of chronic diseases ranging from obesity to diabetes and heart disease (101112).

The Zone Diet puts a strong emphasis on protein intake. High consumption of protein with every meal or snack is a great way to promote muscle growth and repair. Since many people do CrossFit to improve their muscle size and strength, it’s clear why the Zone is considered beneficial in this department.

How to Follow the Zone Diet?

As seen above, the Zone Diet works by carefully planning the intake of specific nutrients so that you get energy for workouts, appetite suppression, and everything you need for optimal athletic performance and weight loss. But dividing these nutrients in percentages may seem tricky, which is why classifying nutrients into blocks can help.

Block is a way of measuring the intake of protein, carbohydrates, and fat. The main purpose of these blocks is to support nutritional balance in your meals. These blocks are:

  • 1 protein block – 7g of protein
  • 1 carbohydrate block – 9g of carbs excluding fiber
  • 1 fat block – 1.5g of fat

Not everyone needs the same amount of blocks because their number depends on factors such as your gender, size, and levels of physical activity. For instance, an average-sized woman would need 11 blocks of each category a day. An average-sized man would need about 14 blocks.

Counting these blocks can be quite confusing for beginners, but the CrossFit food chart here can help you out. For more precise calculation you can use The Zone Diet body fat calculator here.

Everything starts with the block count. Once you find out that magic number, you can evenly divide the blocks into meals and snacks to make sure all nutrients are in the proper balance.

Let’s get back to the average-sized woman who needs 11 blocks of nutrients a day. She would need to eat three blocks of proteins, carbs, and fat for breakfast, lunch, and dinner. Then, she also needs to eat one block of each of these nutrients for snacks twice a day.

An average-sized man would need four blocks instead of three, but the remainder of the process is the same.

Probably the easiest way to start with the Zone Diet is to try the hand-eye method. As you can conclude by its name here, this method relies only on your hand and eye as the only tools you need to determine how much to eat. Your hands can help you determine the portion sizes. At the same time, five fingers serve as reminders to eat five meals (three big meals and two snacks), but also not to ever go without food for more than five hours. Eye helps estimate portions on the plate.

For instance, one-third of protein would be like the size and thickness of your palm.

What Foods to Eat on the Zone Diet?

Protein is the most significant component of the Zone Diet. Throughout this post, we’ve talked about nutrients to consume on the Zone Diet, but now we’re going to get into details here.

As mentioned above, protein in this diet should be lean. The best options include:

  • Lean beef, lamb, veal
  • Fish and shellfish
  • Egg whites
  • Chicken and turkey breast (all skinless)
  • Low-fat cheese, milk, and yogurt
  • Tofu and other animal-based proteins

When it comes to carbs, you should go for vegetables with a low glycemic index such as:

  • Peppers
  • Cucumbers
  • Tomatoes
  • Spinach
  • Yellow squash
  • Mushrooms
  • Chickpeas

Your diet should also include grains, oatmeal, and barley.

Fruit intake should be little and may include:

  • Apples
  • Oranges
  • Berries
  • Plums

What Not to Eat on the Zone Diet?

The Zone Diet can be quite restrictive as there are a lot of foods you need to avoid, such as (15):

  • Processed foods including breakfast cereals and muffins
  • High-sugar fruits such as grapes, bananas, mangos, dried fruits
  • High-sugar or starchy vegetables like peas, carrots, corn, and potatoes
  • Processed or refined carbs such as pasta, bagels, bread, noodles, and other products made from white flour
  • Foods with added sugar like cakes, cookies, and candies
  • Coffee and tea
  • Soft drinks

If you can’t go through a day without coffee or tea, you may want to keep their intake to the minimum.

Are There Any Shortcomings of the Zone Diet?

Every dietary regimen has its strengths and weaknesses. The Zone Diet is not the exception. Even though this diet is recommended by CrossFit as the best eating pattern to follow, there are some drawbacks you need to bear in mind.

The biggest issue with this diet is the recommended intake of carbs. Such a low consumption of carbohydrates may not be enough for athletes that do CrossFit, known for high-intensity workouts. However, research that evaluates this concern is limited so it would be difficult to say CrossFitters can or cannot get enough carbs from this diet. The point here is to consider this info, listen to your body, and determine whether the Zone Diet is answering your needs or not.

The Zone Diet may not be an adequate choice for men and women with a health condition that requires you to lower protein intake. One such condition is chronic kidney disease. In this case, the Zone Diet could have too much protein and may not benefit you.

Another potential shortcoming of this diet is the limited consumption of saturated fats despite the fact studies show they may have a neutral or positive effect on your health (1314).

The Zone Diet may be tricky to follow for people who have never adhered to any particular diet regimen. Suddenly finding yourself in a situation where you have to calculate how much of each nutrient to eat may seem complicated. Plus, it can be difficult to adhere to low-carb intake. All this can pose a major hurdle at the beginning. However, CrossFit is all about discipline in workouts as well as in nutrition so once you get used to it, it won’t seem that difficult.


CrossFit is popular across the globe. For most people, CrossFit is just a type of HIIT, but it’s more than that. You see, CrossFit is developed as a lifestyle. That’s why it involves both exercise and proper nutrition. Evaluating your diet is important if you want to get the most from these workouts. But CrossFit recommends the Zone Diet as the best approach for reduced inflammation and other problems associated with it. The Zone Diet has been around for decades, but studies on its efficacy are scarce and it can be tricky to follow.


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