Does diet coke break a fast? What men should know about diet soda, insulin, and hunger
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 29, 2025 · 15 min read
Diet Coke and other diet sodas contain essentially no calories, so they technically do not break a fast. But for many men, the sweet taste and caffeine can still shift hormones like insulin and cortisol in ways that can undercut why you are fasting in the first place. “If a guy asks me, ‘does diet ...