If you’ve been exploring ways to boost your metabolism, increase your focus, and support weight management, you may have come across the 20-hour fasting diet. Intermittent fasting in general has gained popularity in recent years due to its potential benefits in health and weight management.
Therefore, many people are curious about the potential fasting 20-hour benefits and how they can incorporate this eating pattern into their day-to-day routines.
In this article, we’ll take a closer look at how and if fasting for 20 hours can help with improved health and weight loss, and how the eating pattern measures up to other popular intermittent fasting patterns such as the 16-hour fasting diet.
Also known as the ‘warrior diet’, this is a type of intermittent fasting or time-restricted eating pattern that restricts your eating time to just 4 hours a day.
It’s important to note that, unlike other forms of time-restricted feeding diets that only allow water and unsweetened coffee and tea during the fasting window, some proponents of the 20-hour fasting diet say that you can eat during the 20-hour fasting window.
However, you’re limited to just a few servings of raw fruit and vegetables, as well as water and unsweetened coffee and tea. The majority of your calories should be reserved for the 4-hour eating window.
Generally, intermittent fasting is a legitimate option for weight loss, although it isn’t for everyone. Studies on the matter have shown that intermittent fasting can help with weight loss by reducing overall calorie intake, which creates a calorie deficit and results in weight loss over time (1, 2, 3). As it doesn’t require a complicated or restrictive diet or calorie counting, some people find it easier to maintain for long enough to experience significant weight loss.
It’s important to note that most studies on intermittent fasting and weight loss typically employ longer eating windows (up to 12 hours), and there are limited studies specifically on the efficacy of a 4-hour eating window in promoting weight loss.
With that being said, the available studies on the 20:4 intermittent fasting method do suggest that participants can experience some modest weight loss benefits when following this eating pattern:
After 8 weeks, researchers found that the study participants who followed time-restricted feeding (4 hours and 6 hours) reduced their calorie intake by around 550 kcal a day, without counting calories, and also experienced mild weight loss (around 3% of body weight) (4).
Due to the lack of sufficient scientific research into the 20/4 intermittent fasting plan, we can’t tell you with certainty that this fasting pattern will help with your weight loss goals.
However, just because the 20-hour fasting benefits are lacking doesn’t mean you should give up on IF altogether if it’s a good fit for you. As shown in the section above, there is scientific evidence that suggests that fasting methods with longer eating windows can be beneficial for weight loss. The key to success is to find a strategy that helps you reduce your calorie intake and that fits well with your lifestyle so you can stick with it long enough to see meaningful weight loss.
Together with weight loss, it is suggested that intermittent fasting provides other health benefits, such as:
Read more: Does Fasting Help Lose Face Fat?
After 20 hours of fasting, your body is usually in the third stage of the four stages/cycles of fasting. This third stage, which is also known as the ‘fasting stage’, usually starts after 18 hours of going without food and can last up to 48 hours if you keep going without consuming any calories in that time frame.
In this stage, almost all the glucose (which comes from ingesting carbohydrates) has been used up by the body, and thus, you enter lipolysis. This then leads to (9)
If you’re curious about the 20-hour fast autophagy, it should be noted that 20 hours may be too short a fasting period to trigger this. While researchers still haven’t pinpointed exactly when autophagy starts, some have theorised that it occurs between 24 and 48 hours of fasting (10, 11, 12).
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A 20-hour fasting diet is on the more extreme end of intermittent fasting diet plans, and would likely be considered unsafe for some people to do once a week, let alone every day.
However, if you’re convinced that this is the eating plan that will finally turn your life around, improving your weight loss and health, we recommend that you seek advice from a healthcare professional.
They will advise you on whether you’re eligible to follow this eating plan, and they can also consider your current health and show you how to safely follow this plan with minimal risks to your health.
As stated above, the 20:4 intermittent fasting plan is one of the more extreme IF plans – the other being the 23:1 diet or OMAD – and so it is likely unsuitable for most people.
However, if you want to try it, you can start with once a week and take note of how your body reacts to it.
This will help you see if you can survive this IF eating plan and could also help you determine if there are any benefits of a 20-hour fast once a week in your life.
Check out this article to learn more about the potential benefits of a 20-hour fast.
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If you insist on following this fasting plan, here are some tips that could help you safely get through this diet:
This is particularly important for those with an underlying medical condition or who are taking medication. Most health conditions and some medications can’t go hand-in-hand with fasting, especially such a long fast. Therefore, to avoid any complications, consult a healthcare professional for guidance before you attempt this fasting plan.
This is particularly important if you’re a beginner to fasting. You need to train your body – and yourself – to go for prolonged periods without food, before you jump headfirst into the 20/4 intermittent fasting plan.
Start with the 12:12 plan (12-hour fast, 12-hour eating window), then progress to the 14:10 plan (14-hour fasting window, 10-hour eating window), and then the 16:8 plan before finally attempting the 20-hour fasting diet.
This will help your body slowly get used to intermittent fasting and allow you to try different IF plans. You may even find that you’re more comfortable with the 14:10 or 16:8 plan and have no desire to attempt the extreme 20:4 plan.
Not everyone agrees with this, but if it helps, you can consider consuming small amounts of raw vegetables and fruit to help you get through this long fasting window.
But only with water and other calorie-free drinks like unsweetened coffee and tea. Not only does hydration help with appetite suppression, which means it’ll help you feel less hungry as the day goes by, it may also help prevent/lower the risk of mild fasting side effects such as headaches and dizziness.
Yes, you can. However, it’s recommended to be strategic. Two of the main reasons why many people turn to IF for weight loss are:
At a glance, this means that as long as you fast during the fasting window, you can eat whatever and however much of it you want during the eating window. However, if you dig a little deeper, you’ll discover that if you want to lose weight and improve your health, you have to be mindful of what and how you eat during the eating window.
Instead of eating whatever you want after the 20-hour fast, be smart about your choices.
This helps you not overeat, which further helps with the weight loss goal. The reason intermittent fasting works for weight loss is that it helps you reduce your calorie intake without meticulous calorie counting. So stick with balanced meals and reasonable portions during your eating window.
Especially those that are rich in protein and fiber. Fasting means going hungry for long periods of time, which comes with its own set of side effects. But what if you could reduce the amount of time you spent hungry?
Fiber and protein-rich foods have been shown to help with satiety. This helps you feel fuller for longer and also helps with appetite control, which, as previously mentioned, helps with eventual fat and weight loss.
Read more: Best Foods to Eat Before Fasting: Fuel Your Body Right
Three reasons for this could be:
Contrary to what some people believe, weight loss changes don’t happen immediately. In fact, it may take 6 to 8 weeks to start to see the initial changes in your weight loss. So instead of hopping on the bathroom scale or scrutinizing your body in the mirror, hoping to see changes, wait a while and be consistent with the fast.
As mentioned above, intermittent fasting doesn’t call for calorie counting, which is why it’s such a popular weight loss method for many people. Unfortunately, not counting calories can lead to undereating or overeating, both of which can lead to weight plateauing or weight gain. Use a calorie counter, at least for a while, to better understand how much you should be eating, which will help you with weight loss.
Yes, diet alone can help with weight loss. However, diet and increased physical activity offer the best results in both fat and weight loss. Try to exercise for at least 30 minutes a day, 5 days a week through cardio or strength training, or better yet, a mix of both, and you’ll most likely see the desired results.
This is likely due to some hormonal and metabolic changes in your body. It has been theorized that in experienced fasters, after many hours of going without food, their hunger and satiety hormones (ghrelin and leptin) have adapted to the routine, which means they’re less likely to feel hungry even after 20 hours of not eating. Some also say that the transition to using ketones instead of glucose in the fasting stage can lead to appetite suppression, which can mean less hunger, even after 20 hours of fasting. Yes, you can, as long as the coffee in question is unsweetened and without any added cream or milk. You don’t need to fast to cleanse your body. The body already has organs, primarily the liver and kidneys, that cleanse your body daily, with or without fasting. However, if you’re talking about autophagy, which is the cell’s process of clearing out damaged components and recycling them into new ones, then fasting for between 24 and 48 hours may theoretically help with this, but research is still limited. There are no snacks for fasting, as you’re not allowed to consume calories during the fasting window. Only plain water, unsweetened coffee, and other calorie-free beverages are allowed.Frequently Asked Questions
Why don’t I feel hungry after a 20-hour fast?
Can I drink coffee while fasting?
How long should I fast to cleanse my body?
What are snacks for fasting?
Fasting can be a great way to reduce weight and improve health, but only when it’s done safely. While the 20-hour fasting diet may seem appealing as an intermittent fasting diet plan, it should be approached with caution. Not only is it not well researched, but due to its long fasting window, this plan isn’t safe for many people and is definitely not beginner-friendly.
If you want to attempt it, we highly recommend seeking advice from a healthcare professional. You should also try the shorter IF plans mentioned above, as they can help prepare your body for such a long fast.
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