Intermittent fasting
An approach that alternates periods of fasting (no calories) with eating windows on a regular schedule (e.g. 16/8, 5:2, eat-stop-eat).
Intermittent fasting (IF) is not a diet but a time pattern of eating. The popular formats:
- 16/8: fast for 16 hours, eat within an 8-hour window
- 5:2: eat normally 5 days, severe restriction (500 calories) 2 days
- Eat-Stop-Eat: a full 24-hour fast 1-2 times a week
- Alternate-day fasting: fasting days alternating with normal days
Documented effects: weight loss (via a natural calorie deficit), improved insulin sensitivity, anti-inflammatory effects and autophagy (cellular clean-up) after about 12-18 hours of fasting.
A fresh angle: intermittent fasting is nothing revolutionary. Humans historically fasted regularly (because of food availability). But in our modern societies of 24/7 food abundance, it is very difficult psychologically.
The great myth: fasting speeds up metabolism. False. Basal metabolic rate slows slightly. Weight loss comes from an overall calorie reduction, not from metabolic magic.
An underestimated danger: in women of reproductive age, prolonged fasting can disrupt hormonal cycles (secretion of oestrogen and progesterone). Gentle IF (12/12) is generally fine; extreme formats (24 hours+) need care.
Also: fasting is not advisable for people with a history of restrictive eating, growing teenagers or pregnant women.