In lab studies, saccharin has been shown to cause inflammation of the liver and to inhibit the growth of probiotic bacteria in the gut. It does not appear to interfere with autophagy during a fasted state. ... All of these qualities make it an excellent option for getting a little sweet hit without breaking your fast.

Do artificial sweeteners affect fasting?

You can eat most artificial sweeteners when fasting. No study has been able to prove that sweeteners provoke an insulin reaction. No insulin reaction and no calories will mean you're still in a fasted state.

Is artificial sweetener OK on intermittent fasting?

If you are super strict and want to be 100% sure that you are staying in a fasted state, it is a good idea to stay away from artificial sweeteners all together while fasting. In fact, if you REALLY want to make sure this is the case, it is best to stick to just water with the occasional black coffee.