Does diet coke break a fast? What the science actually says
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 29, 2025 · 14 min read
Diet soda has almost no calories, so most people assume it is “fasting safe.” The real answer is more nuanced: diet coke will not technically break a fast, but it can still nudge hormones, hunger, and some of the very benefits you are fasting for. “From a pure calorie standpoint, diet soda does not break ...