Intermittent fasting: what does science really say?

Intermittent fasting includes several dietary protocols based on alternating periods of eating and fasting. The most popular, 16/8, involves concentrating meals into an 8-hour window.

Different protocols

• 16/8: fast for 16 hours, eat within an 8-hour window (the most studied and simplest)
• 5:2: eat normally for 5 days, restrict to 500-600 kcal for 2 days
• Eat-Stop-Eat: fast for 24 hours once or twice a week
• OMAD: one meal a day (little studied, potentially risky)

What studies show

• Weight loss: comparable to classic caloric restriction. Intermittent fasting is no better but may be easier for some people to follow.
• Insulin sensitivity: improvement observed in several trials, interesting for type 2 diabetes prevention.
• Inflammation: reduction of some inflammatory markers (CRP, IL-6).
• Longevity: promising data in animals, but not yet confirmed in humans.

Limitations and precautions

• Contraindicated for pregnant women, children, people with eating disorders
• Risk of compensation: eating more during the eating window cancels the benefit
• Food quality remains more important than timing

The best diet is the one you can stick to long-term. Intermittent fasting is a tool, not a miracle solution.