Intermittent Fasting: What is it, and how does it work?

Research shows that intermittent fasting is a way to manage your weight and prevent or even reverse some forms of disease. But how do you do it? And is it safe?

With intermittent fasting, you only eat during a specific time. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help your body burn fat. Scientific evidence points to some health benefits, as well. Johns Hopkins neuroscientist Mark Mattson has studied intermittent fasting for 25 years. He says that our bodies have evolved to be able to go without food for many hours, or even several days or longer. In prehistoric times, before humans learned to farm, they were hunters and gatherers who evolved to survive and thrive for long periods without eating.

Nowadays, TV, the internet and other entertainment are available 24/7. We stay awake for longer hours to catch our favorite shows, play games and chat online. We’re sitting and snacking all day and most of the night.

Extra calories and less activity can mean a higher risk of obesity, type 2 diabetes, heart disease and other illnesses.

Scientific studies are showing that intermittent fasting may help reverse these trends.

How does intermittent fasting work?

There are several different ways to do intermittent fasting, but they are all based on choosing regular time periods to eat and fast. For instance, you might try eating only during an eight-hour period each day and fast for the remainder. Or you might choose to eat only one meal a day two days a week. There are many different intermittent fasting schedules.

After hours without food, the body exhausts its sugar stores and starts burning fat. This change is called metabolic switching.

Intermittent fasting works by prolonging the period when your body has burned through the calories consumed during your last meal and begins burning fat.

It’s important to check with your doctor before starting intermittent fasting. Once you get his or her go-ahead, the actual practice is simple. You can pick a daily approach, which restricts daily eating to one six- to eight-hour period each day. For instance, you may choose to try 16/8 fasting: eating for eight hours and fasting for 16.

It can take two to four weeks before the body becomes accustomed to intermittent fasting. You might feel hungry or cranky while you’re getting used to the new routine.

During the times when you’re not eating, water and zero-calorie beverages such as black coffee and tea are permitted.