16/8 intermittent fasting involves eating only during an 8-hour window and fasting for the remaining 16 hours. It may support weight loss and improve blood sugar, brain function and longevity. Eat a healthy diet during your eating period and drink calorie-free beverages like water or unsweetened teas and coffee16/8 intermittent fasting involves limiting consumption of foods and calorie-containing beverages to a set window of eight hours per day and abstaining from food for the remaining 16 hours.This guide reviews 16/8 intermittent fasting, how it works and whether it's right for you.