Drinks · ~230 kcal per mug (1 tbsp butter + 1 tbsp MCT oil)
Does bulletproof coffee break a fast?
Yes, for most goals. Butter and MCT oil take bulletproof coffee to about 230 kcal, which breaks weight-loss, autophagy and gut-rest fasts.
Full answer: Does Coffee Break a Fast? Black Coffee and Every Add-In
The answer for each goal
Weight loss
Breaks fastAutophagy
Breaks fastGut rest
Breaks fastBlood sugar
SafeBulletproof coffee is black coffee blended with butter and MCT oil. With a tablespoon of each, the mug holds about 230 kcal. Roughly 100 come from the butter and 130 from the oil. Ghee coffee uses clarified butter, so it lands in the same range.
On the four goals this site uses to sort answers, bulletproof coffee breaks a weight-loss fast. Its 230 kcal are far past the 50-calorie rule of thumb, a rough guide with no official status. It breaks autophagy and gut rest as well, since the gut has a tablespoon of butter and one of oil to digest. The database marks it safe only for blood sugar.
If a mug of bulletproof coffee is how you start the day, count it as your first meal. Start your eating window from it, and keep to plain black coffee in the fasting hours before it. Collagen coffee is a lighter case, with about 35 kcal for a 10 g scoop of collagen.
Watch out
Bulletproof coffee is often sold as fasting-friendly. At about 230 kcal a mug, it ends a fast for every goal except blood sugar.
Questions people ask
Does bulletproof coffee break a fast?
Yes, for weight loss, autophagy and gut rest. A tablespoon each of butter and MCT oil adds about 230 kcal. The database rates it safe only for a blood-sugar fast.
Can I have bulletproof coffee on a 16:8 schedule?
Yes, as the first meal of your eating window. Drunk in the fasting hours, it ends the fast for most goals. A tablespoon of MCT oil on its own has about 130 kcal.
Related answers
Coffee with cream
A tablespoon of heavy cream has about 50 kcal. It is safe for blood sugar, grey for weight…
MCT oil
Yes, for most goals. A tablespoon of MCT oil is about 130 kcal of fat, so it breaks a fast…
Black coffee
No. Black coffee has about 2 kcal a cup and no sugar, so it keeps a fast for weight loss, …