The choice of diet is an individual one. It’s a matter of finding out what works and is sustainable. Having some science to back up that choice doesn’t hurt, either.
So that’s what we’ve presented here in relation to IF. Of course, it goes without saying that not every study has been included. And, as always, you should seek medical advice before starting a dieting journey.
There are two main approaches to IF: alternate-day fasting and time-restricted eating. With alternate-day fasting, people fast every other day by eating either no calories or one small meal containing 500 to 600 calories. The 5:2 diet is an example of this type of diet, where a person eats normally five days a week and fasts for two.
With time-restricted eating, people fast every day by reducing the window during which they consume calories to between four and 10 hours. Someone following the 16:8 diet, for example, fasts for 16 hours a day and limits their food intake to an eight-hour stretch. Let’s look at time-restricted diets first.
A of young resistance-trained men found that the 16:8 diet improved health-related biomarkers and decreased fat mass after eight weeks. In 2018, a of obese adults found that being on the 16:8 diet for 12 weeks led to weight loss of around 3% and a drop in systolic blood pressure (the top number). In a from 2023, researchers fed mice during a six-hour window and fasted them for the rest of the day (for humans, that’s the equivalent of around 14 hours of fasting ti.