How Dirty Fasting Can Help or Hinder Your Weight Loss Progress

What is dirty fasting? How can it help or hinder your weight loss progress? These are the two main questions I am going to address today.

What is Dirty Fasting?

It’s pretty simple: dirty fasting means you are consuming calories during your fast. Technically, anything with calories breaks a fast. However, depending on how your body reacts, what types of calories and how many calories you are consuming, you may still be able to call your fast “fasting” even if you consume calories. That’s what we refer to as “dirty fasting.”

Before we discuss how dirty fasting can help or hinder your weight loss progress, let’s spend a moment looking at the foods that are close enough to zero calories to be considered “safe.”

Clean Fasting

Once you understand what you can safely consume without breaking your fast, it will be easier to talk about dirty fasting.

Fasting experts agree you can drink the following without breaking your fast:

  • Black coffee (only 2 calories in a cup): Coffee may even induce autophagy!
  • Green, oolong, and black tea (2 calories in a cup): Contain calorie restriction mimetics, which induce autophagy.
  • Most herbal teas: Make sure they don’t contain additives and fruit.
  • Apple cider vinegar (3 calories in 1 Tbsp)
  • Stevia: May lower blood sugar and improve metabolic health.
  • Carbonated water: Flavored is fine, make sure there are no other additives.
  • Lemon juice

(From my post What Breaks a Fast and What Doesn’t: A Comprehensive Guide.)

Dirty Fasting

When you consume anything else, you move into the “dirty fasting” zone. Here are some common foods that are consumed during a dirty fast:

  • Coconut oil
  • Butter
  • Coconut milk
  • Heavy cream
  • MCT oil

You probably have heard about bulletproof coffees. These fatty coffees are made with butter, MCT oil or coconut oil. They are pretty popular in the world of intermittent fasting. That would definitely be an example of dirty fasting (if you drink your bulletproof coffee during your fasting window).

As you can see fats are the main food that is allowed during dirty fasting. That’s because even though fats have calories, and a lot of them, they may not elicit an insulin response. The idea is that as long as you are not inducing an insulin response, you are still reaping the benefits of fasting.

How Dirty Fasting Can Help or Hinder Your Weight Loss Progress

Since the point is to determine if dirty fasting could be beneficial to you, I am going to explain how it can help or hinder your progress and then you can judge for yourself.

How Dirty Fasting Can Help

Dirty fasting has a few advantages. The main one is that consuming healthy fats may actually increase your ketone levels.

Boosts Ketone Levels

Healthy fats, particularly those that contain medium-chain triglycerides (MCTs), like coconut oil and MCT oil, are rapidly absorbed by the liver. They can be used for energy or converted into ketones. MCTs have been used to induce ketosis in children with epilepsy. Moreover, a moderate carb diet can produce effects similar to the ketogenic diet when accompanied by an increase in MCTs consumption. For example, in this particular study, epilepsy patients were consuming 19% carbs (compared to the 5% typical of the keto diet) and 71% fat (at least 40% came from MCTs). They still experienced a very low percentage of seizures despite the higher percentage of carbs.

Most likely, you don’t suffer from epilepsy, but higher ketone levels may help make you feel more energic, improve your mood, increase your focus, and make your fasting easier. If you are curious to find out for yourself how your body is responding to your dirty fasting, you can always purchase a ketone monitor. Measure your ketone levels before and half an hour after consuming your fatty coffee, for example. If you don’t have a ketone monitor, you can purchase the Keto Mojo using my affiliate link to receive 15% off.

Gives You a Feeling of Satiety

Another way you can benefit from dirty fasting is that it will make you feel fuller. More ketones may contribute to decreasing your appetite, but the calories in the form of fat will also help you not feel hungry in and of themselves. I put coconut milk in my coffee and I have tested it compared to regular cream. I find the fatty coconut milk makes me feel full for a lot longer. Depending on what types of fats you pick, you may notice that fasting is easier. You just don’t feel hungry.

How Dirty Fasting Can Hinder

I can think of two main ways dirty fasting could hinder your progress: it could provoke an insulin response and increase your caloric intake.

May Trigger an Insulin Response

If you measure your blood glucose half an hour after drinking your coffee (you can do so with your Keto Mojo) and notice that it rises, be aware that the accompanying insulin response means you are officially losing some of the healing benefits of your fast. Moreover, it will take longer for your body to start producing ketones.

Increases Your Calorie Intake

It’s no secret that fats are calorie-dense. A bulletproof coffee can contain as much as 440 calories (remember, to lose a pound a week, you need a calorie deficit of 500 calories a day!). So, even though some claim a bulletproof coffee can help speed up weight loss by boosting your metabolism, I would be careful about consuming that many calories in a coffee if you are looking to lose weight. You certainly can try it if you would like, just keep it in mind in case our weight loss stalls.

In Summary

For me, dirty fasting has been a lifesaver. My whole fat coconut milk makes my morning coffee ritual more enjoyable. It makes me feel full and satisfied. It may not be the case for you. You may enjoy your black coffee and find that dirty fasting is hindering your weight loss progress. Like everything else, it’s all about creating a regimen that you can sustain and that you find effective.