There is no single rule for “how many hours before,” because timing depends on your goal and tolerance. For appetite control, some people take a diluted amount shortly before eating. For post-meal glucose support, taking it near mealtime can make more sense. If you have reflux or a sensitive stomach, taking vinegar too far before meals (on an empty stomach) may worsen burning. The safest approach is to test a diluted, low dose and choose a timing that does not trigger symptoms.