Intermittent fasting protocols explained
| Protocol | Fast | Eating Window | Best for |
|---|---|---|---|
| 14:10 | 14 hours | 10 hours | Beginners |
| 16:8 | 16 hours | 8 hours | Most people — most researched |
| 18:6 | 18 hours | 6 hours | Intermediate IF practitioners |
| 20:4 | 20 hours | 4 hours | Experienced fasters |
| 5:2 | 2 days restricted | 5 normal days | Those who prefer weekly flexibility |
What breaks a fast?
Water, black coffee, and plain tea do not break a fast. Anything with calories — including milk, cream, sugar, gum, or supplements with fillers — technically breaks a fast.
How to use your results
Start with 14:10 or 16:8 if you're new to intermittent fasting. The most common pattern is skipping breakfast and eating noon to 8pm (16:8).
The total calories within your eating window matter most. Intermittent fasting doesn't create a calorie deficit automatically — you still need to eat within your target calories. Use the TDEE calculator to find your baseline.
Most people adapt to 16:8 within 1–2 weeks. Initial hunger during the fasting window is normal and decreases as your body adapts to the new meal timing.
Frequently asked questions
Does intermittent fasting work for weight loss?
Yes — multiple meta-analyses confirm IF produces weight loss similar to continuous calorie restriction. The main mechanism is reducing total calorie intake by limiting eating hours. It also reduces insulin levels, which may improve fat mobilisation.
Can I drink coffee while fasting?
Black coffee (no milk, sugar or cream) does not meaningfully break a fast. It actually enhances fat burning and reduces hunger. Plain water, sparkling water, and plain tea are also fine during the fasting window.
Is 16:8 the best IF protocol?
16:8 is the most researched and most sustainable protocol for most people. It fits naturally with social eating patterns and allows for a satisfying eating window. 14:10 is easier for beginners; 18:6 is more effective but harder to maintain.
Can I exercise while fasting?
Yes — fasted exercise is safe and may enhance fat burning. Keep intensity moderate to high-intensity training within your eating window when possible. Have protein immediately after fasted workouts to support muscle recovery.
Will intermittent fasting cause muscle loss?
Not if protein intake is adequate (1.6–2.0g/kg body weight) and resistance training is maintained. The eating window needs to include sufficient protein. IF combined with resistance training can maintain or build muscle while losing fat.
How long until I see results with IF?
Most people see 1–2 kg weight loss in the first 1–2 weeks (mostly water and glycogen). Actual fat loss becomes noticeable after 4–6 weeks of consistent practice combined with appropriate calorie intake.
Is intermittent fasting safe for everyone?
IF is not recommended for: pregnant or breastfeeding women, people with eating disorder history, type 1 diabetics, those on blood sugar medications, or children/adolescents. Consult a doctor if you have health conditions.
What should I eat during my eating window?
Focus on whole foods: lean protein, vegetables, fruits, whole grains, and healthy fats. IF doesn't change what you should eat — only when. Poor food choices during the eating window will still prevent weight loss.