Does sugar-free gum break a fast?

Ask Dr. Jason Fung

Does sugar-free gum break a fast? Is it a good idea to have one cheat day per week?

It’s time for this week’s Q&A about intermittent fasting and low carb with Dr. Jason Fung:

Does sugar-free gum break a fast?

I fast by skipping breakfast. I worry that gum is breaking my fast unintentionally. Everyone says something different!


Technically yes, sugar free gum would not be allowed on a fast. But the amount of sugar alcohol in a stick of gum is so small that it likely makes no difference. If you are doing well with gum, then continue. If you are not getting the results you think you should, then cut it out. But I wouldn’t worry a lot about gum, unless you are eating a lot of it.

Dr. Jason Fung

Cheat day while on LCHF and intermittent fasting

If I am on an LCHF and on alternate day fasting diet, is it better to have one cheat day a week, or not?

Thank you,

It’s not better to have a cheat day unless it allows you to follow a stricter diet otherwise. Some people do well, and others not. I don’t recommend a cheat day in general.

Dr. Jason Fung

Q&A videos

Top Dr. Fung videos


Intermittent fasting for beginners

A keto diet for beginners

Earlier Q&A

Intermittent fasting Q&A

More with Dr. Fung

All posts by Dr. Fung

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