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20:4 Intermittent Fasting (The Warrior Diet)
Updated on January 31, 2024
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Diet / Weight Loss
20:4 Intermittent Fasting (The Warrior Diet)
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Fasting is when you voluntarily skip food or water for some time. If you want to lose weight, fasting intermittently is one way of doing it.

Intermittent fasting is an eating pattern where you fast and feed within a given time frame. It promotes calorie restriction by giving you a smaller eating window.1

What Is 20:4 Intermittent Fasting?

The 20:4 intermittent fasting method involves undereating for 20 hours and feasting for 4 hours each day.2

It’s also known as “The Warrior Diet,” a term first coined by Ori Hofmekler in his book of the same title. The general idea is to limit your food intake to one meal per day. This is preferably done at night, without counting calories.3  Hofmekler compares the eating schedule to how ancient warriors trained for battle.

20:4 Intermittent Fasting (The Warrior Diet) 2

20:4 Fasting — What to Eat During Your Fast

During a 20-hour fasting period, you can consume small amounts of:

  • Dairy products
  • Hard-boiled eggs
  • Fresh fruits
  • Raw vegetables 

Preferably, you should avoid foods that have carbohydrates, such as bread and grains. You must focus on eating healthy foods and limiting your consumption of processed ones.

You’re also encouraged to take in plenty of non-calorie fluids. Beverages that you can drink include water, black coffee, and unsweetened tea. 

Refrain from adding sweeteners or cream to avoid added calories. Caloric beverages such as juice, sodas, and shakes are off the table since they are also high in sugar.

What to Eat After a 20:4 Fast

After the 20-hour fasting period, you can generally eat anything. But it would be best if you still watch what you eat.

Pick nutritious, unprocessed, and organic foods. It helps you make the most out of intermittent fasting. Try to aim for a balanced diet in every meal prep. 

Most nutrition experts often recommend the Mediterranean dietas a guideline for eating healthy. This diet plan suggests whole grains, leafy greens, healthy fats, and lean protein.4

You may be worried about whether the longer fasting period can prompt you to overeat. Studies show that you’re just as likely to binge eat compared to other diets.

This means the 20-hour fasting period doesn’t necessarily trigger you to overindulge when it’s your feasting window already.

Health Benefits of Intermittent Fasting 20:4

Some consider 20:4 intermittent fasting protocol or the Warrior Diet a little extreme. The Warrior Diet supposedly mimics the lifestyle of ancient warriors who ate little during the day and feasted at night.

The 20:4 fast or the Warrior Diet is not yet backed by science. However, early evidence suggests that limiting your meals help with fat loss and lowers your risk for cardiovascular diseases.6

The Warrior Diet may share the same benefits as other types of intermittent fasting. Some possible benefits of 20:4 intermittent fasting are:

1. Weight Loss

Studies show that intermittent fasting helps with weight loss. It restricts your calories and reduces your overall intake. It can help you achieve a caloric deficit.

Research further shows that people who eat one meal within a 4-hour window can lose more weight than those who eat calorie-controlled meals. 

The intermittent fasting used in the study mimicked that of the Warrior Diet.6

2. Blood Sugar Control

In type 2 diabetes, your body's insulin resistance causes your blood sugar levels to increase. Research shows that a fasting goal of 18 to 20 hours a day might improve your blood sugar control.7

However, a more recent study suggests that intermittent fasting has risks of hypoglycemia or low blood sugar levels.8

If you have diabetes or other insulin sensitivity, please seek your doctor’s advice before starting the Warrior Diet. They can guide you through safe intermittent fasting or suggest other diet plan that are appropriate to your current health.

3. Reduce Inflammation

Toxins produced during metabolism cause oxidative stress. This can damage essential cell structures, like proteins and DNA.9

Oxidative stress may lead to chronic inflammation linked to heart diseases, diabetes, and some cancer. 

Intermittent fasting can help your body fight inflammation. Study shows that intermittent fasting helps reduce inflammatory cells in the blood circulation. 

During the fasting period, these pro-inflammatory cells enter sleep mode and become less inflammatory.10

4. Repairs Cells

Intermittent fasting helps repairs the cells in your  body.

Our body has a cell repair process known as autophagy. The body recycles structures inside each cell and removes unusable parts. It gives way for new cell structures to be built.11

Research shows that intermittent fasting and exercise help promote autophagy. Autophagy is vital to prolonging cellular health. 

5. Promotes Brain Health

Intermittent fasting slows aging by reducing the effects of free radicals on your tissues. These free radicals are unstable by-products of metabolic processes in the body. They can cause damage to your cells.

Intermittent fasting also helps boost your brain function and helps you resist diseases. During your fast, your body switches to ketones for energy. This change fights brain fog and makes you more alert.12

Side Effects of 20:4 Intermittent Fast

You may experience unpleasant side effects while doing the Warrior diet or 20:4 intermittent fasting. Reactions to watch out for includes:

  • Hunger
  • Fatigue
  • Insomnia
  • Nausea
  • Headaches

Experts suggest consulting with a nutritionist or dietitian before starting intermittent fasting. 

Generally, the 20:4 fast isn’t advised for pregnant women, lactating mothers, and people with eating disorders and health conditions. 

Intermittent Fasting 20:4 vs. 16:8 — Which is Better?

The Warrior Diet may sound like the 16:8 form of intermittent fasting. However, it has a shorter eating period — among other differences:

  • In the Warrior Diet, you are fasting most of the day. Compared with the 16:8 intermittent fast, you spend most of the fasting period asleep, making it easier to sustain.
  • You can have small portions of the suggested foods (e.g. hard-boiled eggs, non-starchy vegetables) during your 20-hour fast. While at 16:8 intermittent fasting, you can’t have any food during the fasting window.
  • The feeding window makes a big difference between 20:4 and 16:8 intermittent fasting.The 4-hour period may be too short to meet your daily calorie intake and nutrient needs. 
  • It’s easier to reach your nutritional and caloric needs in the 8-hour feeding window. You'll have a longer time to squeeze in your daily caloric intake and nutrition.

The original Warrior diet emphasizes the types of food you should be eating. It helps with caloricrestriction throughout the day, especially during your fasting period. 

On the other hand, the modern version of 20:4 intermittent fasting is more relaxed. It allows you to eat whatever you want during your 4-hour feeding window. 

The original Warrior Diet also includes an exercise plan to help maximize the fitness and weight loss benefits while dieting. Of course, you can always pair it with exercise and a healthier lifestyle.

Updated on January 31, 2024
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She has a B.S. in Psychology and enjoys writing about health and wellness.
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