What Is the Warrior Diet?

The Warrior Diet

Verywell / Debbie Burkhoff

At Verywell, we believe there is no one-size-fits-all approach to a healthy lifestyle. Successful eating plans need to be individualized and take the whole person into consideration. Prior to starting a new diet plan, consult with your healthcare provider or a registered dietitian, especially if you have an underlying health condition.

The Warrior Diet is an intermittent fasting protocol developed by health and fitness author Ori Hofmekler. The diet is essentially an extended period of fasting followed by a short period of feasting. Hofmekler created the Warrior Diet in 2001 after years of observing himself and his colleagues in the Israeli Special Forces. His book, "The Warrior Diet: Switch on Your Biological Powerhouse for High Energy, Explosive Strength and a Leaner, Harder Body," explains how to get started on the plan and maintain it for the long term.

Fasting is not a new concept. Perhaps the earliest records of fasting date back to ancient Greece, when philosopher Pythagoras touted the virtues of fasting. Hippocrates and other prominent healers like the Renaissance doctor Paracelsus were also advocates of fasting.

Today, fasting, better known as intermittent fasting, has become a popular practice in the wellness world due to positive results from a number of weight loss studies.

Intermittent fasting is much like it sounds: a period of fasting followed by eating. The intervals vary in length depending on which protocol you follow. The Warrior Diet requires fasting for 20 hours and then feasting for 4 hours. The feasting portion encourages consuming 85% to 90% of calories during this window. This can be up to 1,800 calories in one sitting for someone on a typical 2,000 calorie weight-management plan, or up to 2,700 calories in one sitting for an active person who needs 3,000 calories per day.

While the weight loss effects are promising, the Warrior Diet lacks scientific evidence and is generally not recommended by nutrition experts. Most research to date has examined less extreme iterations of intermittent fasting, which means Hofmekler's 20:4 protocol may not be effective or healthy for everyone.

What Experts Say

“The Warrior Diet is a stricter type of intermittent fasting, alternating between 20 hours of undereating and 4 hours of unlimited intake. Experts worry this diet may lead to nutrient deficiencies and warn that it is inappropriate for many groups (like athletes or people who are pregnant).”
Chrissy Carroll, RD, MPH

What Can You Eat?

Those who follow the Warrior Diet will fast for 20 hours during the day and overnight, and then overeat during a four-hour window in the evening. This method is based on the idea that our primitive ancestors spent their days hunting and gathering and would feast at night.

During the fasting window, Hofmekler suggests sustaining yourself on small portions of dairy, hard-boiled eggs, and raw produce. You can also drink zero- or low-calorie beverages like water, coffee, and milk. It's a good idea to consume a few servings of fruits and vegetables throughout the day in order to ensure you get enough essential vitamins and minerals.

There are no restrictions during the 4-hour feeding window. While that technically means you could eat nothing but pizza, it's recommended to consume healthy, nutrient-dense foods like fruits, vegetables, and protein. Whole-grain foods, such as sprouted wheat bread, quinoa, rice, bulgur, and oatmeal are all great options for fueling up during your eating window. Protein, as well as raw and full-fat dairy foods, are strongly encouraged; Hofmekler is a fan of cheese, yogurt, and raw milk.

It’s important to note that the Warrior Diet isn’t based on science in the clinical sense—instead, the 20:4 protocol is based on Hofmekler’s own observations and opinions on the tactics he used to stay fit during his time in the military.

What You Need to Know

During the 20-hour fasting period, you should consume only minimal calories. When it’s time for your feeding window, you can essentially eat however much of whatever you want until the four hours are over. You can determine your feeding window based on a timeframe that works well for you, but most people save their feast for the evening hours.

When it's time to feast, Hofmekler suggests centering your meals on healthy fats and large portions of protein, specifically dairy protein sources such as cheese and yogurt. There’s no need to count calories on the Warrior Diet if you follow Hofmekler’s suggestions and focus on unprocessed foods. The key component of this protocol is timing. The plan is based on the idea that long periods of fasting and short windows of overeating lead to optimal health, fitness, and body composition.

Because there aren’t any modifications to the Warrior Diet, if you deviate off of the 20:4 protocol, you wouldn’t be on the Warrior Diet anymore. However, there are other intermittent fasting protocols that may be more beneficial and have more research behind them. Here's how they compare:

  • 16:8 diet: Followers of this popular intermittent fasting method eat all of their calories for the day in an 8-hour window and fast for the remaining 16 hours of the day. The 16:8 method is popular for beginners because you should be asleep for about half of your 16 fasting hours.
  • 5:2 diet: This method involves eating how you normally would on five days of the week, and eating only 500 to 600 calories on the other two days. This is another popular fasting protocol, though the fasting portion may cause binge eating.
  • Eat Stop Eat diet: This method involves a complete 24-hour fast once or twice a week. For example, if you stop eating at 8 p.m. on Saturday night, you wouldn't eat again until 8 p.m. on Sunday night.
  • Alternate-day fasting: When following this protocol, you would eat in an ongoing cycle: Fast one day, eat normally the next, and so on. Usually, fasting days allow for 500 to 600 calories.

There’s plenty of research on the health benefits of intermittent fasting in general, but there is little evidence on the Warrior Diet protocol. Keep this in mind when deciding whether or not to try this plan.

What to Eat
  • Fruits and vegetables

  • Whole grains

  • Raw and full-fat dairy products

  • Animal and plant protein

  • Zero-calorie beverages

What Not to Eat
  • High-sugar processed foods

  • High-sodium processed foods

  • High-sugar beverages

Protein

Those who follow the Warrior Diet are urged to consume large amounts of protein. Protein is essential for maintaining and building muscle mass, a key goal of the Warrior Diet.

Sugary Processed Foods

Packaged sugary foods are one of the main culprits behind many chronic diseases, including diabetes and inflammatory bowel disorders. The Warrior Diet recommends keeping added sugar to a minimum.

Salty Processed Foods

Even though they might seem healthier than sugary foods, salty snacks can be just as problematic for your blood sugar and other health markers. If you’re looking for something crunchy and savory to snack on, try veggies with hummus or guacamole. You can also make your own savory snacks at home to avoid processed options.

Sugary Beverages

The Warrior Diet guidelines suggest limiting intake of soda, energy drinks, and juice with added sugars. Sugary beverages are a leading cause of weight gain, tooth decay, and chronic diseases.

Pros and Cons

Pros
  • May aid weight loss

  • May improve blood sugar

  • May help with inflammation

  • May improve cognition

Cons
  • Lacks evidence

  • Difficult to follow

  • May lead to binge eating

  • Many potential side effects

  • Nutrient deficiencies

  • Not appropriate for everyone

While our paleolithic ancestors may have easily gone 20 hours without food, that’s not the norm in modern society. Fasting for 20 hours every day can be difficult and lead to severe cravings and extreme hunger. Some people may experience obsessive thoughts about food during the fast.

As a result, it could be easy to consume too many calories during the 4-hour feasting window. It may also be a challenge to consume enough servings of fruits and vegetables, since carb-heavy and protein-dense foods could seem more appealing.

Still, preliminary evidence links intermittent fasting, including 20-hour cycles, to weight loss. Fasting, in general, is strongly associated with improvements in blood sugar control and insulin sensitivity. This potential benefit can be lost, however, if you eat foods high in carbohydrates and/or sugar during your eating window.

Emerging research suggests that intermittent fasting may help fight inflammation and improve cognitive function, but more human studies are still needed to confirm whether this effect may also protect against cognitive decline. Also, this research was not conducted using the Warrior Diet 20:4 protocol.

There is insufficient evidence-based scientific research legitimatizing the Warrior Diet beyond the extrapolated concept of intermittent fasting.

Is the Warrior Diet a Healthy Choice for You?

The U.S. Department of Agriculture's 2020–2025 Dietary Guidelines for Americans recommends consuming a variety of nutrient-dense foods including:

  • Vegetables of all types; dark, leafy greens, red and orange, legumes (beans and peas), starchy, and other
  • Fruits, especially whole fruits
  • Grains, at least half of which are whole grains
  • Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages
  • A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products
  • Oils
  • Limited saturated fats, added sugars, and sodium

On the surface, the Warrior Diet adheres to federal guidelines since it encourages the consumption of whole fruits and vegetables, dairy products, whole grains, and protein. However, since you are also free to choose whatever foods you want, there’s no guarantee that you will consume the right amount of nutrients unless you specifically follow Hofmekler's advice as outlined in the book. You may also find it difficult to get the right balance of different food groups within the 4-hour feasting window.

The Warrior Diet doesn’t specify calorie intake. In fact, Hofmekler discourages calorie counting and instead says you should just stay focused on maintaining the 20:4 fasting ratio. But for many people, it's important to have a sense of how many calories should be consumed each day whether the goal is to lose, maintain, or gain weight.

Most people need an average of 2,000 calories per day for weight maintenance and around 1,500 per day for weight loss but these numbers vary based on age, sex, height, weight, and activity level. Use this calculator to determine your own daily calorie needs.

It may not be realistic for everyone to try to consume the recommended amount of nutrient-dense foods in just four hours. While some aspects of the Warrior Diet are considered healthy, it is not a balanced eating plan.

Health Benefits

Inflammation is a leading cause of disease, including heart disease, diabetes, some cancers, bowel disorders, and more. Research suggests that some types of intermittent fasting could help fight chronic inflammation, but there is no evidence directly linking the Warrior Diet or the 20:4 fasting protocol to these benefits.

Consistent alternate-day fasting has also been shown to help overweight people lose a substantial amount of body fat and decrease the risk of cardiovascular disease. But long-term studies in large diverse groups are still needed to better understand the link between intermittent fasting and weight loss. And while intermittent fasting may improve blood sugar, there is no evidence directly linking 20:4 fasting to these benefits.

Health Risks

Fasting for 20 hours straight may cause severe cravings and intense hunger, which could lead to overeating and contribute to weight gain. Depriving your body of substantial calories can also cause fatigue, brain fog or difficulty focusing, “hanger”, mood swings, stress, anxiety, dizziness or lightheadedness, hormonal disruptions, and more.

Certain groups of people should not follow the Warrior Diet, including anyone who is pregnant or breastfeeding. People with diabetes should avoid this protocol since research on the safety of intermittent fasting for this population is still lacking. Additionally, those who take medications that must be accompanied by food should also avoid this diet.

Most research about intermittent fasting focuses on Ramadan, alternate days of caloric restriction, the 16:8 protocol, and the 5:2 protocol. More evidence is still needed to know if the Warrior Diet protocol is effective and to understand any potential side effects or drawbacks.

A Word From Verywell

Intermittent fasting can help you reach your health goals if done properly, but so can any other diet or lifestyle that encourages whole, nutritious foods. If you want to try intermittent fasting, the Warrior Diet may not the best place to start. Instead, explore evidence-based plans like the 16:8 protocol or 5:2 method. The Warrior Diet is tough to stick to, especially for beginners, and it lacks scientific evidence.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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17 Sources
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