[Q&A] What does and does not break a fast?


The answer depends on what type of fasting you want to do:

1. Non-caloric fasting

Fasting method that does NOT allow any food or drink with caloric value during the fasting window.

- Faster weight loss
- Promotes autophagy (recycling of cells)

- Might not be sustainable for extended periods for some people

The following will not break a non-caloric fast:
- Water
- Black coffee
- Unflavored tea / Green tea / Herbal tea
- Diet soda *
- Sugar-free gums and mints *

* Not recommended. Contains non-caloric sweeteners that can lead to cravings for sweet, high-calorie foods.

2. Fat fasting

Fat fasting is a method that allows for the consumption of small amounts of healthy fat during the fasting window. 

The idea behind a fat fast is that consuming small amounts of fat can trigger only minimal insulin production and have minimal to no effect on blood glucose levels, making it a possible alternative to other forms of fasting. 

- Maintains ketosis even when consuming calories
- Feel satiated even when fasting (which allows you to fast longer)

- Slower weight loss (body uses ketones from food instead of your fat stores)
- Increased caloric consumption

The following will not break a fat fast:
- Anything listed on non-caloric fasting
- Bulletproof coffee (Coffee + Butter + MCT Oil)
- Bone broth

For additional resource, here's Dr. Berg answering the question,

'Does bulletproof coffee break a fast?'