Do sweeteners break a fast?

The impact of sweeteners on fasting is a topic with mixed evidence. Andrew Huberman notes that artificial sweeteners may cause a transient increase and then decrease in blood glucose levels, potentially increasing hunger, but the effect can vary depending on the type and amount of sweetener used. Plant-based non-sugar sweeteners like Stevia generally have minimal impact on overall blood glucose over time, and in moderation, these are likely okay during fasting periods. However, some individuals might experience an increase in hunger just by tasting something sweet, which could make fasting more difficult. Therefore, it's recommended to monitor personal responses possibly with a continuous glucose monitor (1).

Furthermore, the perception of sweet taste, even from non-glucose-increasing sweeteners like Stevia, might not significantly disrupt fasting or metabolic pathways. In a discussion on this topic, it was mentioned that the overall impact of these sweeteners is relatively minor compared to the effects of high sugar intake (2).

Thus, while there is not a definitive answer due to individual variations and the mixed nature of the data, artificial sweeteners in moderation do not typically break a fast for most people, but individual responses may vary.