Yes, most people can drink Coke Zero during a fasting window without technically “breaking” the fast, especially if the goal is weight loss or simple time-restricted eating.

How Coke Zero Affects Fasting

Coke Zero has essentially zero calories and no sugar, so it does not contribute meaningful energy intake or directly raise blood glucose in most people. For fasting focused mainly on calorie control or weight loss, this usually means it is allowed in moderation.

However, it contains artificial sweeteners and caffeine, which can have subtle metabolic effects. Some people show small insulin responses or increased appetite and sugar cravings after sweet-tasting zero-calorie drinks.

When It Might Be a Problem

If your main goals are deeper metabolic benefits (like improving insulin sensitivity, gut rest, or maximizing autophagy), many experts recommend avoiding diet sodas during the fast. Artificial sweeteners may affect the gut microbiome and could interfere with some of these stricter health-focused fasting goals, even without calories.

People who notice that Coke Zero triggers hunger, cravings, or overeating later may find that it indirectly harms their fasting results. In those cases, sticking to water, black coffee, or plain tea is usually better.

Practical Recommendations

• For weight loss or basic intermittent fasting: Coke Zero in moderation is generally fine, but do not rely on large amounts daily.

• For insulin sensitivity, gut health, or autophagy: Prefer water, black coffee, and unsweetened tea; avoid or minimize Coke Zero during the fasting window.

• Pay attention to your own response: if it boosts cravings or makes fasting harder, skip it and use non-sweet drinks instead.