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 Coke typically does not break a strict, calorie‑based fast because it contains about 0–5 calories per serving. But its non‑nutritive sweeteners can still activate sweet‑taste receptors and the gut–brain axis, potentially nudging insulin, gut hormones, and hunger—and quietly dulling some fasting benefits in certain people. “From a pure calorie standpoint, diet soda does not ...