Does coffee break a fast?


The impacts of coffee on fasting are somewhat nuanced. Here are a few key points from discussions featuring Dr. Rhonda Patrick and other experts:

  1. Circadian Rhythm and Metabolism: Dr. Rhonda Patrick discusses how even black coffee, which is non-caloric, can influence metabolic effects and circadian rhythms. Caffeine in coffee can reset peripheral clocks in organs like the liver, potentially impacting the functionality of fasting and time-restricted eating schedules 1 2.

  2. Impact on Autophagy: Both Satchin Panda and Dr. Rhonda Patrick explain that coffee contains polyphenols that can actually trigger processes like protein deacylation, which may promote autophagy, a cellular cleaning process. This indicates that coffee might have some beneficial roles even during fasting periods 3 4.

    Coffee and Fasting

    Satchin explains how coffee affects the circadian clock and its impact on fasting. Rhonda asks about coffee intake during intermittent fasting and how it affects the fasting window.

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  3. Practical Implementation: Dr. Patrick also mentions that, strictly speaking, anything other than water breaks a fast. However, she suggests that she personally considers it a break of fast if it isn't water, except for small exceptions like brushing teeth 5.

  4. Health Effects: Dr. Guido Kroemer discusses studies where coffee, caffeinated or decaffeinated, was shown to beneficially induce autophagy in mice, suggesting potential health benefits in humans. However, the exact impact on fasting's metabolic benefits can vary 4.

In conclusion, while black coffee might influence certain metabolic pathways and circadian rhythms, existing research also suggests potential benefits. Therefore, it may be permissible depending on individual fasting goals and definitions. Always consider personalized approaches and, if needed, consult healthcare professionals.