Fasting Timer

16:8 means 16 hours of fasting and an 8-hour eating window each day. Example: stop eating at 8 PM, eat next at noon — that's 16 hours fasted, 8 hours window. It's the most popular intermittent fasting pattern because it fits easily — you essentially skip breakfast or eat dinner early. During the fasting hours, only water, black coffee, plain tea, and other zero-calorie drinks are allowed. 16:8 has shown modest benefits for weight loss, insulin sensitivity, and metabolic health in studies — though most benefits come from the natural reduction in total calories rather than fasting itself.

Plain water, black coffee (no milk, no sugar, no sweeteners), plain tea, herbal tea, and unsweetened sparkling water. Sparkling water and electrolytes (without calories) are fine. Anything with calories breaks the fast — milk in coffee, juice, soft drinks, even bone broth (technically). Some IF approaches allow up to 50 kcal during the fast for tolerance ('dirty fasting'). For the strictest benefits — autophagy, full insulin response — stick to zero-calorie drinks only. Avoid artificially sweetened drinks during the fast if possible; some studies suggest they may trigger insulin response in sensitive people, though evidence is mixed.

It can, mainly through reducing total calorie intake by limiting eating hours. Studies show 16:8 leads to 1–3% body weight loss over 8–12 weeks compared to no intervention — modest but real. The benefit isn't magic; it's calorie restriction made easier by skipping a meal. Some people find IF easier to sustain than counting calories all day. Others overeat in the eating window and lose nothing. IF works best when combined with overall food awareness and protein-rich meals. Compared to standard calorie restriction at the same total intake, IF doesn't appear to give additional fat loss benefit in most studies.

Start with 12:12 — 12 hours fasting (overnight) and a 12-hour eating window. Almost everyone can do this naturally. Once comfortable, extend to 14:10, then 16:8 over a few weeks. Don't start with longer fasts (18:6, 20:4, OMAD) — they're harder to sustain and risk triggering binge eating. Stay hydrated. Have your last meal include protein and fibre to keep you full longer. Expect mild hunger, irritability, or low energy in the first 1–2 weeks as your body adapts. If symptoms persist beyond that, IF may not be right for you. Slow ramping is the key to consistency.

Plain black coffee — no milk, no sugar, no cream — doesn't break a fast for most practical purposes. It contains negligible calories (under 5 kcal/cup) and has a mild appetite-suppressing effect that helps during fasts. Adding milk, cream, or sugar does break the fast. Bulletproof coffee with butter and MCT oil definitely breaks the fast. Even artificial sweeteners may cause minor insulin response in some people. If your goal is fat loss, plain black coffee is fine. If your goal is autophagy or strict metabolic fasting, go for water-only fasts. For most people, plain black coffee is acceptable.

OMAD (one meal a day) is a strict 23:1 protocol — fasting 23 hours, eating one meal. It can work for some adults but isn't suitable for everyone. People who shouldn't try OMAD: pregnant or breastfeeding women, those with diabetes (especially on insulin), eating disorder history, low body weight, growing teenagers, anyone with low blood pressure or hypoglycemia issues. Even healthy adults often find OMAD hard to sustain — getting all daily protein and micronutrients in one meal is challenging. For most people, 16:8 or 18:6 give similar benefits with less rigidity. OMAD should be approached cautiously and discussed with a doctor if you have any health conditions.