Intermittent fasting (IF) has become one of the most popular ways to diet. But is it better than simply eating less?
Common approaches
- 16:8: eat within an 8-hour window each day.
- 5:2: eat normally five days a week; around 500–600 kcal on two non-consecutive days.
- Alternate-day fasting: alternate normal days with very low-calorie days.
What the research shows
Randomised trials comparing intermittent fasting with standard daily calorie restriction generally find similar weight loss when total calories are similar. IF works mainly by making it easier for some people to eat less — not through a special metabolic effect.
Who it suits
- People who aren't hungry in the morning.
- People who prefer fewer, larger meals.
- Those who find a simple time rule easier than counting.
Who should be cautious
People with diabetes (especially on medication), those who are pregnant or breastfeeding, anyone with a history of disordered eating, and under-18s should avoid fasting regimes unless advised by a health professional.
Make it work
- Hit your protein target within your eating window.
- Don't overcompensate when the window opens.
- Stay hydrated during the fast.
- Keep training — it protects muscle.