Compute your fasting and eating windows by protocol: 16:8, 18:6, 20:4, OMAD, 5:2 or alternate-day fasting.
Your day in 24 h format
- Eating8 h
- Fasting16 h
Intermittent fasting concentrates your intake in a narrower window of the day. The most-used protocols are 16:8 (16 h fasting / 8 h eating), 18:6, 20:4 and OMAD (one meal a day).
What the evidence says
Recent meta-analyses (Cochrane 2023, Patikorn 2021) show weight loss similar to a standard hypocaloric diet, not superior. Effects on fasting glucose and insulin are modest. The main advantage is adherence: fewer meals to plan, less night-time snacking.
How to start
Ramp up progressively: 12:12 the first week, 14:10 the second, 16:8 from the third onward. Black coffee, tea or water during the fast. If you train, do it at the end of the fast or after the first meal depending on how you feel. Not recommended during pregnancy, breastfeeding, eating disorders or growing adolescents.
Frequently asked questions
Does intermittent fasting help you lose weight?+
If there's a calorie deficit, yes. The 2023 Cochrane review shows weight loss similar to a standard hypocaloric diet. The advantage is adherence, not a magic metabolic effect.
Can I drink coffee or tea while fasting?+
Yes, no sugar or milk. Water, herbal teas and fat-free broths also don't break the fast.
Is it safe?+
For healthy adults, yes. Not recommended during pregnancy, breastfeeding, eating disorders or growing adolescents.