During fasting, plain water is the baseline drink, and unsweetened tea or black coffee are commonly treated as compatible additions. The idea is to stay hydrated and, if desired, use caffeine for alertness without adding calories that would meaningfully interrupt the fast.
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“When you are fasting, regardless of how long, I know you're ingesting fluids like water and presumably some caffeine.”
Andrew Huberman · Essentials: The Biology of Slowing & Reversing Aging | Dr. David Sinclair · Oct 30, 2025 · 16:45 · YouTube ↗