Most people treat intermittent fasting like a flexible suggestion. They start at eighteen hours, then sixteen feels fine, then the kitchen opens at hour fourteen and nobody knows.
An eighteen-hour window only works when it is a daily rule, not a mood. The rule is simple: no caloric food or drink until you have fasted eighteen hours — water, black coffee, and plain tea are fine.
Solo apps log after you eat. Accountability groups ask before you break the fast. That one question — did you complete your window today? — is harder to negotiate than a timer you can ignore.
LetBeMe is habit structure, not medical advice. Talk to a clinician if fasting is new to you or you have health concerns.
Finish your 18 hours before eating. Check in with your group first.