What Is Dirty Fasting? How To, What You Can Eat + Benefits

The practice of fasting for weight loss and health has been around for thousands of years, and there are now countless iterations of intermittent fasting diets. 

But, what is dirty fasting?

In this diet guide, we will discuss dirty fasting vs clean fasting definitions, how many calories break a fast, the benefits of dirty fasting, what you can eat during a fast, and if dirty fasting works for weight loss.

We will look at: 

  • What Is Dirty Fasting?
  • How Many Calories Break a Fast?
  • What Can You Eat While Dirty Fasting?
  • What Are the Benefits of Dirty Fasting?
  • Does Dirty Fasting Work for Weight Loss?

Let’s get started!

An empty plate and an alarm clock.

What Is Dirty Fasting?

Understanding the dirty fasting definition is best done by first understanding the clean fasting definition.

Water fasting and intermittent fasting diets, where you are only consuming water or non-caloric beverages such as club soda, black coffee, herbal tea, plain black tea, or plain green tea, are all considered forms of “clean fasting.“

For example, the 16/8 intermittent fasting diet is one of the most common intermittent fasting diet schedules that fall under the umbrella of “time-restricted feeding“ or “time-restricted eating. “

This particular type of intermittent fasting diet involves fasting for 16 hours and then confining your eating window to just eight hours per day.

Any iteration of a time-restricted intermittent fasting diet involves abstaining from all food for a designated number of hours per day and then restricting the eating window to the remaining hours that together constitute a 24-hour period.

A plate, alarm clock and a notebook that says intermittent fasting.

Time-restricted eating intermittent fasting diets tend to be the more common approach to intermittent fasting.

This is opposed to other intermittent fasting types, such as alternate day fasting, which instead fluctuates between days of normal eating with any type of eating schedule with days of no eating or fasting for a day.

Prolonged water fasting is an even more strict fasting diet protocol that involves not eating or drinking any caloric substance for an extended period of time, sometimes anywhere from a 24 hour water fast to a 3 day water fast, 5 day water fast, or even 7-day fast.

In contrast to clean fasting, there are modified fasting protocols where you might significantly reduce your caloric intake but consume some food or take in a few calories while “fasting,’ which is referred to as “dirty fasting.”

For example, one form of alternate-day fasting that falls under the umbrella of intermittent fasting diets is the 5:2 diet.

The 5:2 diet involves eating normally for five days a week without the need to restrict your calories. 

A person holding out a glass of water.

During the other two days in the week, you are to reduce your daily caloric intake to one-quarter of your energy needs, which is simplified to be 500 calories per day for women and 600 calories a day for men. 

There are other types of modified fasting diets for weight loss aside from the structured 5:2 fasting diet plan.

Examples include the watermelon fasting diet; juice cleanses that focus primarily on beverages made with lemon juice, cayenne pepper, and maple syrup; drinking Bulletproof coffee (coffee with cream and MCT oil), or a liquid diet.

Most of these modified fasting protocols can also be considered “cleanses“ or “extreme diets“ for rapid weight loss and are sometimes referred to as “dirty fasting” or “partial fasting.”

Essentially, the dieter will consume some amount of food or caloric beverage during the partial fast.

Though these “modified types of fasting“ are not technically true fasting, they may still be grouped together under the umbrella of types of fasting and can still offer the health benefits of fasting with less hunger and fatigue.

Bulletproof coffee.

How Many Calories Break a Fast?

Technically, any caloric intake breaks a fast—at least when considering clean fasting or strict fasting.

There isn’t a specific or set dirty fasting plan in terms of how many calories you can eat for dirty fasting.

In general, most people who practice dirty fasting vs clean fasting may eat or drink about 50 calories while “fasting,” or possibly up to 100 calories.

Of course, by default, the more calories you eat while dirty fasting, the further you are getting away from “fasting, “ and the closer you are getting to normal eating and reducing the benefits of fasting.

All of this said, how many calories you can eat while dirty fasting will depend on your fasting goals, how long you are fasting, your body size and caloric needs, and even what you are eating while fasting in terms of the actual macronutrients.

A person eating an apple.

For example, having cream or butter with bulletproof coffee while dirty fasting will have little impact on your blood sugar levels because fat does not cause an increase in blood sugar and insulin the same way that adding sugar or having some other sweetened food or carbohydrates would.

Thus, if you are fasting to get into ketosis or to improve insulin sensitivity, dirty fasting with fats or having bulletproof coffee while fasting may still help you reach your diet goals with fasting.

On the other hand, adding sugar to your coffee or having a piece of fruit might still qualify as dirty fasting based on how few calories you eat, yet you will compromise your fasting diet goals with the choices of what you eat while fasting.

This is because sugar or other forms of carbohydrates will have an impact on your blood sugar, insulin, and state of metabolic ketosis, whereas only consuming fats should not.

Bone broth.

What Can You Eat While Dirty Fasting?

There are no set rules about what you can eat while dirty fasting.

Again, what to eat while fasting will really depend on your goals with fasting.

The most common foods and beverages that people have while dirty fasting vs clean fasting include the following:

  • Cream or milk in coffee or tea
  • Sweetener in coffee or tea
  • Bone broth
  • Non-starchy vegetables
  • Clear broths and stocks
  • Pre-workout powders or drinks 
  • Low-calorie keto electrolyte powders or drinks
A person drinking a protein shake.

What Are the Benefits of Dirty Fasting?

Advocates of intermittent fasting diets, water fasting, or fasting in general sometimes frown upon dirty fasting or eating anything during a fast.

However, although hard-core or strict fasting protocols do not allow you to eat or drink any caloric foods or beverages, there are some potential benefits of dirty fasting.

Proponents of the dirty fasting approach to weight loss or fasting diet, in general, suggest that the main benefit is that having a little bit of food or consuming a few calories while fasting will allow you to stick with your fasting diet without losing the benefits of fasting.

The main obstacle or hurdle to long-term adherence to an intermittent fasting diet regimen or more strict intermittent fasting diet schedule is that it is very difficult to abstain from eating and drinking for an extended period of time.

Allowing the calculated and disciplined consumption of a few calories or selected foods while dirty fasting can potentially make it easier to stick with a fasting routine.

In this way, dirty fasting can be sort of like a compromise between not fasting at all and strict clean fasting that would otherwise be unsustainable or untenable.

A person holding out their oversized pants showing weight loss.

Does Dirty Fasting Work for Weight Loss?

So, is dirty fasting effective? What are the pros and cons of dirty vs clean fasting? Can partial fasting work for weight loss, or is modified fasting effective?

Ultimately, it is difficult to definitively say whether modified fasting works for weight loss or if you can “cheat“ with dirty fasting and still lose weight or reach your fasting diet goals.

It really depends on what you are eating while dirty fasting and your fasting weight loss or health goals overall.

Because there isn’t a set definition of how much food is permitted to still qualify as dirty fasting or partial fasting vs caloric restriction, it is hard to say whether modified fasting works for weight loss or if you can eat while fasting and still have the benefits of fasting.

You need to consider your goals of fasting in the context of what you are eating during fasting dirty.

If you are just trying to lose weight with fasting, you can get away with eating more while dirty fasting and potentially still reaching your weight loss goals as long as you are fasting long enough and making healthy choices that still keep you in a net caloric deficit.

On the other hand, if you are fasting for ketosis, improved insulin resistance, or some of the other health benefits of fasting, dirty fasting won’t work if you are eating too much while fasting or choosing the wrong foods (sugars, carbs, etc.).

For tips on the best foods to eat to break a fast, check out our guide here.

Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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