What Can You Eat During 4/20 Intermittent Fasting?

Intermittent fasting has been around for quite some time now, but it’s been receiving increased attention in the media as more and more people are catching onto the immense benefits it can provide. Fasting is an excellent way to lose weight, improve metabolism, balance hormones, combat brain fog, increase daily energy, and even increase overall lifespan.

While there are no guarantees every person who tried intermittent fasting will reap all of these results, there’s good evidence that this method of eating works well for many people, and some have even found it to be a life-changing tool to transform their overall health.

One popular type of intermittent fasting is 20/4 intermittent fasting. This method involves fasting for 20 hours (including overnight) and then eating during a 4-hour-long eating window. This is a daily routine that fasters are meant to follow to allow their body to undergo something known as “metabolic switching”. This means the body changes its source of energy from glucose from foods to ketones made from fatty acids.

The metabolic switching aspect of fasting is precisely what makes it so beneficial, and the long fasting length of 20 hours allows the body adequate time to fully go back and forth between these two states.

Who is the 4/20 Diet For?

The 4/20 intermittent fasting diet is moderately intense and shouldn’t be attempted by beginners, those with poor blood sugar control, or anyone with underlying contraindicatory health conditions. Fasting, more broadly, shouldn’t be done by anyone with a history of eating disorders, growing children or teenagers, or those who have diabetes.

With these demographics aside, the 4/20 intermittent fasting diet can be done by anyone with an intermediate amount of fasting experience or beyond. It’s always best to start off a fasting journey with short fasts to see how the body will react before slowly adding on length. 12-hour fasts are a great place for beginners to start with.

It’s also important to learn how to properly nourish yourself during the eating window to support a healthy version of this lifestyle, and this may take some practice. The longer the fast, the shorter the feeding window is, and the more essential it becomes to learn what foods to eat.

What to Eat During The Fasting Window

The goal of an intermittent fast is to consume no calories during the fasting window. This allows the body to burn up all the available glucose in your body for energy and resort to creating ketones for energy. However, it is possible to consume a few low-calorie things that won’t interrupt this process.

Here’s what you can consume while fasting:

  • Water and sparkling water
  • Black coffee
  • Plain black tea, green tea, white tea, and herbal tea
  • Matcha (made with water)
  • Electrolyte drinks
  • No-calorie flavored water
  • Sugar-free gum
  • Amino acids (BCAAs)

While all of these are admissible, some may have a small effect on altering the body’s reaction to the fast. Amino acids, in particular, do contain a small amount of calories, and some amino acids can potentially be converted into glucose via the gluconeogenesis pathway, thereby disrupting the benefits of a fast. As long as the amino acids are taken in small enough amounts, however, it won’t have a large effect, and it can help to increase energy and muscle recovery after workouts.

What to Eat During The Eating Window

Unlike the fasting window, there are no set rules on what you can or cannot eat during the fasting window of intermittent fasting. Technically, you can eat whatever you want, but there are a few important things to keep in mind.


One of the first things to look for in optimal foods at this time is their satiety factor. This means how filling they are and how long-lasting that sensation of fullness is. As a general rule of thumb, fiber, and protein are the most filling nutrients, followed by fat, and lastly by sugar and starchy carbohydrates.

Filling up your plate with a focus on fiber and protein allows for good energy and fullness well into the 20-hour fasting period, making it a much more sustainable option. If someone only ate cookies and bread during their eating window, they would likely find themselves ravenous again in just a few hours, making a 20-hour fast an uncomfortable and possibly impossible task.

Nutrient Density

Another important thing to keep in mind is nutrient density. Since the eating period on a 4/20 fast is only 4 hours, it may be difficult to consume large amounts of food. This is partially what makes it such a great option for weight loss, but it also can make it difficult to get adequate nutrition.

Making sure to select highly nutrient-dense foods will ensure the fast has energy, enough nutrients, and not too many calories so that they look and feel their best. Some of the most energy-dense foods to include are a wide array of vegetables, fruits, lean animal protein foods, nuts and seeds, low-fat dairy, whole grains, and some healthy fats, all in the least-processed form available.



After considering satiety and nutrient density, it’s important to eat a variety of different types of food during the eating window to achieve dietary balance. Selecting whole foods from each food category every day, and ideally at every meal, will allow fasters to cover their nutritional bases and avoid any deficiencies.

Tips to Make 4/20 Fasting Work for You

With these foods in mind, there are a few additional tips to apply to intermittent fasting to make it a sustainable lifestyle. Firstly, going slow and listening to your body is essential. You don’t want to push very far past the limits of discomfort. If you feel shaky, ill, or can’t go about your day-to-day functions, forget your fast and eat.

Secondly, make sure to stay hydrated and try to keep your fasting schedule very consistently at the same times every day. Finally, it’s totally okay not to fast every day. If you feel best fasting Monday to Friday and eating as you wish over the weekend, it will be a more achievable lifestyle for you, and you’ll still gain plenty of benefits.

Always remember each body is unique, and there’s no single diet that will work well for everyone. Fasting is just one excellent tool in a health toolbox of endless options. It can be a powerful way to optimize your health, so it’s absolutely worth a try.