20:4 Hour Fast: Effective and Safe at the Same Time?

So, you’ve mastered other intermittent fasting regimens and want to step it up to the next level? Then the 20:4 hour fast is here to challenge you. This strenuous fasting method is not for the weak-willed. A fast as rigorous as this one makes you wonder: can the 20:4 fast be effective and healthy at the same time? 

Let’s plunge into the world of 20:4 hour fasting and its benefits to determine if the 20:4 fast is good for you.

What Is 20:4 Fasting?

The 20:4 fast is a type of time-restricted eating (TRE). In a 24-hour lapse, you fast for 20 hours and eat the remaining 4 hours. TRE functions by aligning the timing of meals with the body’s natural circadian rhythm (24 hours). TRE fasting does not require you to monitor food intake or count calories, thus permitting a lengthening of the overnight fasting period by 14-20 hours. 

Circadian Rhythm and 20:4 Fasting

The National Institute of General Medical Sciences defines circadian rhythm as the physical, mental, and behavioral changes an organism experiences over a 24-hour cycle. Circadian rhythms affect sleep patterns, hormone release, appetite and digestion, and temperature. 

Alternating feeding and fasting cycles following the circadian rhythm can positively affect nutrient metabolism, regulation of hormones, and physiological processes, therefore improving cardiometabolic health. Simplify your fast by syncing your fasting regimen with your circadian rhythm by using the Fastic app.

Potential Benefits of 20-hour Fasting

What does fasting for 20 hours do to your body? The potential benefits of fasting for 20 hours go from the stimulation of physiological processes to the improvement of mental health. Pre-clinical and clinical studies have demonstrated that intermittent fasting has a wide range of benefits for many diseases, including obesity, T2DM, and hypertension, and improves cardiovascular risk factors. Several early TRE (eTRE) studies reported metabolic benefits, including insulin sensitivity, lipid metabolism, and circadian gene expression.

When performed correctly, practicing a 20-hour fast can:

• Improve insulin sensitivity

• Boost metabolism rate

• Enhance cellular health

• Promote weight loss

• Reduce the risk of heart disease

• Improve mental health and mood

While a TRE fast offers potential benefits, it can also bring potential side effects. Reported adverse effects include, but are not limited to, headaches, mood swings, dizziness, and weakness. Keep in mind that fasting without adequate protein replacement is known to cause muscle wasting. Moreover, during the 4-hour eating window, you should eat whole, unprocessed, nutrient-dense foods. Incorporating these foods into your fast will help replenish the nutrients you aren’t ingesting during fasting.

Your body gets water not only from drinking but also from the food you eat. Therefore, staying hydrated is also vital while fasting.  It is indispensable you compensate for the lack of water intake your body experiences while fasting. 

Can You Lose Weight by Fasting 20 Hours a Day?

Fasting for 20 hours can potentially assist in weight loss because it encourages the body to resort to stored fat (triglycerides) as a fuel source. When our bodies fast, triglycerides break down into fatty acids for energy. The liver then converts these fatty acids into ketone bodies, which supply energy. Our ketone levels rise after 8 to 12 hours of fasting. This rise in ketone production can aid in weight loss efforts. Nevertheless, no two bodies will react the same. Ketone production triggering varies from one person to another. 

Get Started: How To Do the 20:4 Fast?

TRE does not focus on calorie intake; it focuses more on the eating window. So, the method you choose will depend on how intensely you want to go about it. Here are the two most common approaches for the 20:4 fast.

20:4 Fast

The conventional approach to a 20:4 hour fast entails no eating during 20 hours and having a normal meal for the remaining 4 hours. During the fasting hours, you can drink calorie-free beverages, like water with herbs or black coffee, which will not break a fast. To optimize your calorie intake it is encouraged you have your daily meal during daylight hours so it aligns with your natural circadian rhythm. 

Warrior Diet

Inspired by the dietary practices of ancient warriors, fitness expert Ori Hofmekler introduced it as a 20:4 fasting technique back in 2002. The warrior diet is not as intense as its name suggests. It consists of fasting for 20 hours and having an “all-you-can-eat” feast for the remaining 4 hours. While fasting you are allowed small low-calorie snacks like fruits and vegetables.

Although you can drink other calorie-free or low-calorie beverages, water is the weapon of choice. Drinking water does not interfere with your body’s fasting state, additionally, it helps suppress appetite and keeps you hydrated. 

Who Should Do a 20:4 Fast?

Since this type of fast is one of the most arduous out there, it is advised you have ample experience in other time-restricted eating plans (e.g. 16:8 and 18:6). Being familiarized with these kinds of fasting regimens is key to knowing exactly what your body’s limits are.

The 20-hour fast offers flexibility in intensity, where you can easily adjust the level of challenge according to your goals, routine, and commitment. Regardless of whether you have extensive experience in diverse types of TRE or not, you must always pay attention to your body’s signals!

When to Eat During the 20:4 Fast?

The Center for Human Nutrition at UCLA stated that aligning your 20:4 fast with your body’s circadian rhythm will make it easier for your body to adapt and optimize its efforts. It is not recommended you have your only meal too early in the morning since insulin sensitivity is at its lowest and leads to ineffective use of glucose.

Autophagy usually occurs during the night as you sleep because the body enters a fasting state. Recent research recommends you have your eating window be anywhere between the hours of 8 AM to 5 PM or 10 AM to 7 PM. Ultimately, whenever you eat is up to you and whatever works best for your body. 

Is It Safe to Fast for 20 hours Every Day?

Any type of fasting regimen will be safe as long as it is done correctly and you are mindful of your body’s feedback at all times. We suggest you start with less rigorous fasting plans and work your way up the intensity ladder.

As always and with any activity that interferes with the body’s physiological processes, you should seek professional medical guidance before starting any fasting plan. Intermittent fasting is not recommended if you have hormonal imbalances, are pregnant or breastfeeding, or have an eating disorder. Moreover, fasting is not ideal if you suffer from chronic illnesses like diabetes, nutritional deficiencies, and compromised immune systems, among other health conditions. 

All in all: Is the 20-hour Fast Good for You?

All things considered, a 20-hour fast is generally good for you as long as you do it safely and always listen to your body. With TRE fasts you have full decision power of when and how to go about it. Try the Fastic app now and give the 20:4 fast a go.

Disclaimer: It is advised to speak with a health professional before beginning intermittent fasting or a diet program. There may be side effects for people with certain medical conditions.