Coke Zero is a grey area like other diet sodas. With zero calories it will not break a strict-calorie fast, but its sweeteners may cause cravings or a small insulin response in some people, so limit it on a fast.
| Calories | 0 kcal |
|---|---|
| Breaks a weight-loss fast? | Partial |
| Breaks ketosis? | No |
| Breaks autophagy? | Partial |
| Insulin impact | Possible small response |
Coke Zero contains no sugar or calories, so it does not break a fast defined by calorie intake. The uncertainty is the same as with any diet soda: artificial sweeteners may provoke a mild insulin or cravings response in sensitive people, and their effect on autophagy is not settled. It is generally fine for a fat-loss fast and best avoided on a strict autophagy fast.
Judge it by your goal and your body. For appetite control and weight loss, an occasional Coke Zero is unlikely to matter. If it makes you hungrier, or you are fasting for autophagy, choose water, sparkling water, or black coffee instead.
Occasional use is unlikely to matter on a weight-loss fast; daily heavy use is better replaced with water or tea.
FastTrack times your fasts, your eating window and your progress, with a plan built around your goals.
Get your free plan