Does bulletproof coffee break a fast?

Q: Does bulletproof coffee break a fast?

No - breaks a clean fast. Breaks a clean fast. It may fit a keto routine, but it is not a calorie-free fast. Call it a modified fast or first meal, and log it in the eating window.

/ 100

Breaks a fast

Breaks a clean fast

100-400 kcal

No - breaks a clean fasthigh confidenceNutrition-label evidence

Decision

No - breaks a clean fast. Butter, ghee, MCT oil, and coconut oil make coffee calorie-dense.

Reason

It may fit a keto routine, but it is not a calorie-free fast.

Evidence

Added fats are calorie-dense; even one tablespoon of oil or butter can exceed 100 kcal.

How we calculate this value

Base tier: 25/100 for "Breaks a fast". Item adjustment: -17 points for calories, nutrient signal, product variability, and safety caution. Final Fast Score: 8/100.

What to do

Call it a modified fast or first meal, and log it in the eating window.

References for this answer

Methodology

USDA Agricultural Research Service: FoodData Central U.S. Food and Drug Administration: Added Sugars on the Nutrition Facts Label