Is Intermittent Fasting Safe?

This dieting trend is said to inhibit dementia and other age-related diseases. Here are the facts.

- Anna-Kaisa Walker

What is intermittent fasting?

Throughout the course of a 24-hour day, your body naturally cycles between feeding and fasting modes while you’re awake and when you’re asleep. People who practise what’s called intermittent fasting attempt to extend the fasting phase in order to enhance the body’s hormonal regulation processes that kick in when you’re not eating. This way, say the diet’s proponents, you can maintain a healthy weight and, therefore, avoid the risks associated with obesity, including Type 2 diabetes and heart disease.

Intermittent fasting can take several forms. Time-restricted fasting, also called the 16:8 schedule, involves limiting breakfast, lunch and dinner to an eight-hour window—say, 10 a.m. to 6 p.m. A more extreme schedule (which would require a doctor’s okay, especially if you take medication) entails eating as you typically would for five days a week and fasting for two (when you’d still consume plenty of water, and optionally up to 500 calories).