20:4 Intermittent Fasting: How-to, Meal Plan and Results

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Medically Reviewed by Dr. Aman Priya Khanna
Written by Kirti V, last updated on 13 December 2023| min read
20:4 Intermittent Fasting: How-to, Meal Plan and Results

Quick Summary

Intermittent fasting 20/4 is an eating approach where you fast for 20 hours and eat during an 8-hour window. It has several benefits, including weight loss, reduced risk of disease, and improved mental health. To follow this diet, you simply need to eat your first meal of the day at noon and your last meal at 8 pm. You can then fast for the next 20 hours until noon the following day.

Imagine a diet where you do not have to restrict what you eat and only focus on when you eat. That is what intermittent fasting is all about! Intermittent fasting 20/4 is an incredible eating approach that successfully transforms how you look. 

By adopting 20-hour intermittent fasting, you not only shed those unwanted kilos but also experience several other benefits. But what is 20/4 hour intermittent fasting? What are its benefits? And how does it work? Continue reading to find out. 

What is Intermittent Fasting 20/4?

Intermittent fasting 20/4, often called the “Warrior Diet,” is a type of time-restricted eating method.  It takes inspiration from the dietary habits of ancient warriors, who practised minimal daytime eating and feasted at night. It involves a daily fasting period of 20 hours, followed by a four-hour eating window. During the 20-hour fasting period, individuals are advised to incorporate small portions of the following in their diet:

  1. Dairy products
  2. Hard-boiled eggs
  3. Raw fruits and vegetables

Additionally, it is important to stay well-hydrated with non-caloric fluids. After the 20-hour fasting window, people have a four-hour eating window to indulge in their choice of foods. However, selecting wholesome, unprocessed, and organic food options can maximise the potential health benefits of this eating pattern. 

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Weight Loss With 20/4 Intermittent Fasting

20/4 intermittent fasting weight loss varies greatly among individuals and depends on factors like starting weight, diet quality, and activity levels. According to a study by Sofia Cienfuegos et al. in 2020, 20 hours of fasting every day for eight weeks can help lose 3% of body weight. The duration of a 20/4 intermittent fasting plan depends on individual goals and preferences. Many people practise it daily, while others adopt it on specific days. 

When practised responsibly, 20/4 intermittent fasting can be safe for many individuals. However, it may not be suitable for everyone. For a successful outcome, it is advised to start gradually, experiment with different schedules, and stay hydrated. 

Foods to Eat and Avoid in 20/4 Intermittent Fasting

Generally, you can consume any food you like during intermittent fasting. However, some foods are a better choice than others. Mindful food choices during the four-hour eating window can maximise the potential benefits of fasting. 

Foods to Eat in the 20-Hour Window (in small proportions) 

Food/Nutrients

Examples

Fruits


  1. Banana
  2. Mango
  3. Apple
  4. Kiwi
  5. Peach


Raw Vegetables


  1. Carrot
  2. Onions
  3. Mushrooms
  4. Leafy greens


Vegetable Juices


  1. Carrot 
  2. Beet
  3. Celery


Dairy


  1. Yoghurt
  2. Milk
  3. Cottage cheese


Broth


  1. Chicken
  2. Beef


Protein


  1. Hard-boiled eggs
  2. Poached eggs


Beverages


  1. Water
  2. Coffee
  3. Tea



Foods to Eat in the 4-Hour Window

Food/Nutrients

Examples

Cooked Vegetables


  1. Brussel sprouts
  2. Cauliflower
  3. Zucchini


Proteins


  1. Legumes
  2. Chicken 
  3. Eggs
  4. Fish 
  5. Turkey


Dairy


  1. Yoghurt
  2. Milk
  3. Cheese


Fats


  1. Olive oil
  2. Nuts


Starches


  1. Potatoes
  2. Corn
  3. Beans


Grains


  1. Bread
  2. Pasta
  3. Oats
  4. Barley



Foods to Avoid

While there is no rule to eliminate any foods during intermittent fasting 20/4, it is better to avoid some unhealthy choices. These foods can cause stomach issues, which makes it harder to fast. These foods include:

  1. Fast Food: High in unhealthy fats and low in nutrients
  2. Fried Food: Loaded with trans fat, which is detrimental to heart health
  3. Chips: Can lead to overeating
  4. Cookies and Cakes: High in sugar, can cause low energy
  5. Candy: Spikes blood sugar and low nutritional value
  6. Processed Meats: Contains unhealthy fats 
  7. Artificial Sweeteners: May disrupt gut health 
  8. Sweetened Drinks: Causes rapid blood sugar spikes and weight gain

Meal Plan for Intermittent Fasting 20/4

Anyone starting the intermittent fasting plan 20/4 should follow an initial three-phase (three-week) plan. This helps improve your body’s ability to utilise fat for energy. However, make sure to consult your doctor before trying this diet plan. 

Phase I (Week One): Detox

This first week of intermittent fasting 20/4 strives to enhance the body’s ability to eliminate toxins. It also helps the liver neutralise substances that promote weight gain. Practise undereating from waking until your evening meal. You can overeat during the evening meal. 

20-Hour Window

4-Hour Window

Sample Lunch Meal: 

  1. Clear broth soup
  2. A mixed salad with a minimal olive oil and vinegar dressing
  3. A hard-boiled egg

Sample Daytime Snack: 

  1. Carrot
  2. Beet
  3. Parsley
  4. Celery juice
  5. Cottage cheese with fruit

Sample Dinner Meal:

  1. A salad with minimal olive oil and vinegar dressing, to be consumed first
  2. Steamed vegetables like broccoli, zucchini, carrots, and spinach
  3. Legumes and beans like lentils, kidney beans, and black beans
  4. Grains like brown rice, barley, and quinoa (avoid wheat)
  5. Small portions of goat cheese, yoghurt, feta cheese, ricotta, poached eggs

Phase II (Week Two): Adapting to Fat Fuel

In the second week, the diet aims to improve the body’s ability to use fat for energy. The focus of this week is on eating high-fat food like nuts. 

  1. The 20-hour undereating window includes the same food as week 1. 
  2. For the 4-hour evening window, replace grains and starches with protein like legumes, eggs, fish, or meat.
  3. Eat raw nuts like almonds, pecans, and walnuts.

Phase III (Week 3): Adapting to Carb Fuel

The diet plan focuses on the body’s ability to utilise carbohydrates for energy. This approach revolves around a cycle of alternating between high-carb and high-protein meals. It is advised to follow these meal patterns: 

  1. Consume high-carb meals for 1-2 days
  2. Transition to low-carb, high-protein meals for 1-2 days
  3. Return to high-carb meals for 1-2 days
  4. Continue with low-carb, high-protein meals for 1-2 days

The undereating foods are the same as the first two weeks. The four-hour overeating period in phase III is as follows:

High-Carb Days

High-Protein, Low-Carb Days

  1. Salad with oil and vinegar dressing
  2. Cooked vegetables
  3. Small portions of animal protein
  4. One main carbohydrate like potato, corn, rice, barley, pasta, bread, etc.
  1. Salad with oil and vinegar dressing
  2. 227-454 grams of animal protein
  3. Cooked, non-starchy vegetables
  4. A small amount of fresh tropical fruit for dessert

After Week 3

After three weeks, you can alternate between these phases based on your specific requirements. Once you complete these three phases, you can have a glass of wine with a high-protein meal. However, it is important to note that beer and other alcoholic beverages should be avoided.

Note: It is important to consult a nutritionist for a personalised diet plan. 

Benefits of Intermittent Fasting 20/4

Even though intermittent fasting 20/4 is not backed by research, intermittent fasting has proven benefits. Since it is an intermittent fasting approach, it is not wrong to assume that the benefits are also applicable to 20/4 fasting. 20/4 intermittent fasting benefits may include the following:

  1. Weight Management: By restricting calorie intake to a short 4-hour window, many individuals find it easier to create a calorie deficit. This can cause weight loss or weight maintenance. Furthermore, fasting for 20 hours can put you into ketosis (the body burns fat for energy instead of carbohydrates). This metabolic change helps you lose weight. 
  2. Lower Risk of Diabetes: Fasting may improve insulin sensitivity. It promotes blood sugar control and reduces the risk of type 2 diabetes. However, you must consult a doctor before trying 20/4 intermittent fasting. 
  3. Decreased Inflammation: Oxidative stress-induced inflammation can contribute to various illnesses, like heart disease, diabetes, and certain cancers. Intermittent fasting can diminish inflammation within the body.
  4. Improved Brain Health: Intermittent fasting promotes brain health. It regulates inflammatory pathways that influence brain function. Individuals may also experience mental alertness, improving their brains’ capability to think and learn. 

Tips for Intermittent Fasting 20/4

Since 20/4 is a more extreme method of intermittent fasting, it is advised that you do your research beforehand. To help you start and maintain your 20/4 fasting experience, consider these helpful tips:

  1. Start Gradually: If you are new to intermittent fasting, start with a shorter fasting window, such as 16/8. Intermittent fasting 16/8 vs. 20/4 includes the difference in the hours of fasting. Once you are comfortable with 16/8 (16 hours of fasting and 8 hours of eating), gradually work up to 20/4. 
  2. Explore Various Schedules: Experiment with diverse meal combinations and timing strategies to discover the most suitable approach for your needs. During the four-hour eating window, you can choose a single big meal or distribute your intake across a few smaller meals and snacks.
  3. Stay Hydrated: Drink lots of water during fasting to stay hydrated and help manage hunger. You can also choose non-caloric beverages like green tea, black coffee, or lemon or cucumber-flavoured water. 
  4. Pre-plan Your Meals: Strategically planning your meals can prevent impulsive consumption of unhealthy snacks during your eating window. Get creative by incorporating nutritious and tasty foods into your meal plans.
  5. Prioritise Nutrient-Rich Foods: To maximise the advantages of intermittent fasting 20/4, emphasise whole, nutrient-rich foods. Include fruits, vegetables, lean proteins, nuts, seeds, legumes, and healthy fats in your diet. Steer clear of trans fat, processed foods, and sugary snacks and beverages.
  6. Listen to Your Body: Be flexible and adjust your fasting schedule based on your energy levels, activity level, and overall well-being. If you feel energetic and clear-minded, 20/4 can be a good choice. However, if you feel tired and cannot think clearly, consider other options for weight loss. 
  7. Consider Nutritional Supplements: A daily multivitamin and mineral supplement can be beneficial for meeting your nutritional requirements during fasting. It lowers the risk of nutrient deficiencies.
  8. Consult a Doctor: Before starting any fasting regimen, it is vital to consult a medical specialist. This is especially important if you have underlying medical conditions or are taking medications.

Is Intermittent Fasting 20/4 for Everyone?

No, 20/4 hour intermittent fasting, like any fasting regimen, is not suitable for everyone. Fasting can affect individuals differently, and its appropriateness depends on various factors. These factors include your overall health, medical conditions, and personal preferences. It is not suitable for the following people:

  1. Children under 18 or adults above 65 years of age
  2. Women who are trying to conceive, pregnant, or breastfeeding
  3. Individuals who are underweight (a body mass index less than 18.5)
  4. Those with an eating disorder or a history of one
  5. Athletes or those who are extremely active
  6. People who have a medical condition like heart failure, type 1 diabetes, or cancer
  7. Those who take prescription medications 

Risks and Side Effects of Intermittent Fasting 20/4

Despite the potential benefits of intermittent fasting 20/4, there are some drawbacks that you must be aware of. The risks and side effects of 20/4 intermittent fasting include:

  1. Disordered Eating: The short eating window may lead to overeating or binge eating. This is especially true if individuals feel overly restricted during fasting.
  2. Difficulty Sustaining: For some individuals, sticking to a strict 20-hour fasting window can be difficult, leading to inconsistent fasting patterns. It can be particularly challenging when engaging in social activities such as brunch or lunch outings.
  3. Nutritional Deficiency: Inadequate intake of essential nutrients during the four-hour eating window may lead to nutritional deficiencies if not carefully planned.
  4. Lack of Long-Term Research: While intermittent fasting shows promise, there is limited long-term research on the safety and benefits of 20/4 fasting. 
  5. Other Side Effects: Intermittent fasting can have various side effects, although they may not affect everyone equally. Common side effects include:
    1. Fatigue
    2. Dizziness
    3. Lightheadedness
    4. Low energy
    5. Extreme hunger
    6. Irritability or mood swings
    7. Hypoglycemia (low blood sugar)
    8. Stress or anxiety
    9. Insomnia
    10. Fainting
    11. Constipation
    12. Hormone disruptions
    13. Weight gain

Intermittent Fasting 16/8 vs 20/4

Intermittent fasting offers various approaches. 16/8 and 20/4 are amongst the most popular. In the 16/8 method, you fast for 16 hours and eat during an 8-hour window daily. The 20/4 method includes fasting for 20 hours with a 4-hour eating window. The key difference is the fasting duration, impacting calorie intake and potential benefits.

  1. The 16/8 method is more flexible and might be easier for some. It offers benefits like weight loss, improved insulin sensitivity, boosted metabolism, and enhanced brain function. 
  2. The 20/4 method offers a more extended fasting period. It offers the same benefits as 16/8 but may lead to quicker results. 

The choice depends on individual goals, lifestyle, and adaptability. Consulting a doctor or dietitian is recommended to determine the best fit for your needs.

Takeaway

Intermittent fasting 20/4 offers a unique approach to eating. It can promote weight management, improve insulin sensitivity, and offer other health benefits. Its flexibility makes it accessible to many individuals seeking to improve their well-being. However, it is essential to consider individual health needs and consult a doctor before adopting any fasting regimen.

You can get in touch with HexaHealth for all your medical concerns. We will offer personalised recommendations and help you connect with the best doctors near you. With HexaHealth, you can take control of your health and achieve your wellness goals. Schedule an appointment TODAY! 

Suggested Reads

Right Way to Break Intermittent Fasting - Expert's Guide
7 Days Indian Diet Plan for Intermittent Fasting
Intermittent Fasting 14/10: Meal Plan, Benefits & Results
30 Days Intermittent Fasting Results - Ultimate Guide

Frequently Asked Questions

The intermittent fasting 20/4 method involves fasting for 20 hours and consuming all daily calories within a 4-hour eating window. It aims to promote weight management and potential health benefits by limiting food intake to a specific period daily.

5 tips to get started with 20-hour intermittent fasting include:

  1. Start Gradually: Transition from shorter fasting windows to 20/4.
  2. Experiment With Different Schedules: Try different time options to see what works best. 
  3. Plan Balanced Meals: Ensure nutrient intake within the 4-hour eating window.
  4. Stay Hydrated: Drink water and non-caloric beverages during fasting.
  5. Listen to Your Body: Adjust the schedule based on hunger cues.

The intermittent fasting plan 20/4 works in three phases over three weeks with different aims. 

  1. Phase I (week 1): removes toxins 
  2. Phase II (week 2): the body utilises fat for energy 
  3. Phase III (week 3): the body utilises carbs for energy 

The 20/4 intermittent fasting can boost metabolism by improving insulin sensitivity and promoting fat utilisation for energy. It can lead to improved weight management and metabolic health.

The best time to start 20:4 intermittent fasting depends on your lifestyle. Some people prefer an early-morning eating window to get energy for their workout. Others may succeed with a late afternoon or evening eating window to align with work and social activities. Choose a time that suits your schedule and helps you maintain consistency.

Foods that you can eat during the 4-hour eating window include:

  1. Cooked vegetables like Brussels sprouts and cauliflower
  2. Proteins like chicken and eggs
  3. Dairy like yoghurt and milk
  4. Fats like olive oil and nuts
  5. Grains like oats and barley

20/4 intermittent fasting benefits include:

  1. Weight management
  2. Boosts brain health
  3. Decreases inflammation
  4. Improves blood sugar control

20:4 intermittent fasting is not backed by research. However, intermittent fasting is proven to reduce weight loss and provide other health benefits. Since 20:4 fasting is an extreme form of other intermittent fasting plans, it can help you see results.

Yes, intermittent fasting 20/4 can be suitable for weight loss. Restricting calorie intake to a 4-hour window creates a caloric deficit needed for weight loss. Moreover, fasting for 20 hours puts your body into ketosis (using fat for energy). This metabolic shift can help you lose weight.

A sample meal plan may differ based on the time of your eating window. 20:4 intermittent fasting sample plan for an early eating window may include:

  1. 8 AM: Apple slices with nut butter 
  2. 9:30 AM: Avocado toast with a fried egg
  3. 11 AM: A glass of blueberry smoothie
  4. 12 PM: A bowl of chicken and vegetable salad

Yes, you can drink water and black coffee during the 20-hour fast. However, avoid calorie-additives like milk or sugar in the coffee.

The duration for 20:4 intermittent fasting can vary from one individual to another. You should assess its impact on your well-being to understand the right duration.

Potential health risks with 20:4 intermittent fasting are as follows:

  1. Brain fog
  2. Disordered eating 
  3. Nutrient deficiencies
  4. Side effects like hunger, dizziness, fatigue, etc. 

The best eating schedules for intermittent fasting include:

  1. The 16:8 diet
  2. The 5:2 method
  3. Alternate day fasting 

20:4 is an advanced form of intermittent fasting that is not suitable for everyone. This fasting schedule may not be suited for you if you:

  1. Have a BMI less than 18.5
  2. Are pregnant, breastfeeding, or trying to conceive
  3. Are below 18 or above 65 years old
  4. Have an eating disorder or a history of one
  5. Have a medical condition

The 20:4 intermittent fasting method has a 20-hour fasting period and a 4-hour eating window. Compared to other fasting methods like 16:8 or 5:2, it involves a more extended fasting period and may have more health benefits.

The timing of the intermittent fasting eating window depends on the lifestyle and personal preferences. People usually prefer a late evening meal and skip breakfast in the morning.

Yes, you can exercise on intermittent fasting 20/4. However, you should pair your workouts with your eating windows to avoid working out on an empty stomach.

Intermittent fasting 20/4 can be safe for many people when practised carefully. However, it may not suit everyone, particularly those with certain medical conditions. Consult a doctor before starting this fasting regimen to ensure it is safe for you.

The pros of intermittent fasting 20:4 include:

  1. Helps with weight loss
  2. Decreases insulin resistance
  3. Improves brain health
  4. Decreases inflammation

Cons of intermittent fasting 20:4 include:

  1. Long fasts
  2. Hunger and cravings
  3. Disordered eating 
  4. Side effects

Both 20/4 and 16/8 methods can cause weight loss. If you want to trigger autophagy (the body’s process of reusing old cell parts), rest your gut, or enter ketosis, longer fasts like 20/4 may be better than 16/8.

You should break your 20-hour fast with a nutritious meal. This includes veggies, proteins, and healthy fats.

The frequency of 20-hour fasting per week varies based on individual goals and preferences. You should fast for 20 hours as many times as you feel good.

The warrior diet is an eating pattern that involves long periods of undereating and short duration of overeating. Individuals on a warrior diet must fast daily for 20 hours, followed by an eating period of 4 hours.

References

All the articles on HexaHealth are supported by verified medically-recognized sources such as; peer-reviewed academic research papers, research institutions, and medical journals. Our medical reviewers also check references of the articles to prioritize accuracy and relevance. Refer to our detailed editorial policy for more information.


  1. Kubala J. The Warrior Diet: Review and Beginner’s Guide [Internet]. Healthline. Healthline Media; 2018. link
  2. Everything to know about The Warrior Diet. Medical News Today [Internet]. 2020 Dec 22; link
  3. Vasim I, Majeed CN, DeBoer MD. Intermittent fasting and metabolic health. Nutrients [Internet]. 2022 Jan 31;14(3):631. link
  4. The warrior diet: Pros, cons, how to follow it, and example meal plan [Internet]. www.medicalnewstoday.com. 2020 [cited 2023 Oct 26]. link
  5. Canning K. The 16:8 Diet Might Be The Best Version Of Intermittent Fasting For Weight Loss [Internet]. Women’s Health. 2019. link
  6. Leonard J. Six ways to do intermittent fasting: The best methods [Internet]. www.medicalnewstoday.com. 2022. link

Updated on : 13 December 2023

Disclaimer: The information provided here is for educational and learning purposes only. It doesn't cover every medical condition and might not be relevant to your personal situation. This information isn't medical advice, isn't meant for diagnosing any condition, and shouldn't replace talking to a certified medical or healthcare professional.

Reviewer

Dr. Aman Priya Khanna

Dr. Aman Priya Khanna

MBBS, DNB General Surgery, Fellowship in Minimal Access Surgery, FIAGES

12 Years Experience

Dr Aman Priya Khanna is a well-known General Surgeon, Proctologist and Bariatric Surgeon currently associated with HealthFort Clinic, Health First Multispecialty Clinic in Delhi. He has 12 years of experience in General Surgery and worke...View More

Author

Kirti V

Kirti V

B.A. English | M.A. English ( Magadh University, Bihar)

3 Years Experience

With 3 years of full-time experience as an SEO content writer, she has honed her skills to deliver captivating and persuasive writing that leaves a lasting impact. She is always ready to learn new things and expand...View More

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