How (and Why!) Intermittent Fasting Works

By: Contributor

Intermittent fasting is a diet that focuses not on what you eat, but on when you eat. It is a dieting pattern that is grounded in the thought that not eating for a set period of time can cause significant weight loss, improve metabolic health, serve as preventive care for many diseases and lead to a longer life.

That sounds great. How does it work?

Intermittent fasting is simple, and its roots date back centuries. Many ancient cultures practiced intermittent fasting for religious purposes, and many people continue to do so today. But since its principles don’t align with most of the popular diets (it’s rare that a diet plan tells you to skip breakfast, let alone several meals), adopting it takes patience and the willingness to accept some growing pains.

Contrary to popular belief, the weight loss that occurs while you’re intermittently fasting isn’t just due to the consumption of fewer calories. Sure, that definitely helps, but the main benefit of intermittent fasting is how it affects the way that your body actually digests food. When you don’t eat for an extended period of time, your body doesn’t receive energy from a food source, and is therefore forced to pull energy from its fat supply, which causes weight loss. This can also help build muscle during workouts when you’re intermittently fasting.

What are the different methods of intermittent fasting?

There are several popular plans for intermittent fasting — we’re going to cover the top three: the 16/8 cycle, the 5:2 diet and the eat-stop-eat method.

The 16/8 cycle involves fasting for 16 hours straight and only eating within a specific window of eight hours. So, for instance, if you begin eating at noon, you’ll need to stop eating at 8:00 pm. Under this method, many people find that they’re able to get away with skipping one meal a day (usually breakfast). You can customize this plan to the timeframe that best fits your lifestyle, but the trick is to stay within it so your body burns the optimal amount. It’s important to note that you can still drink non-caloric beverages (like water, unsweetened tea and black coffee) during the fast.

The 5:2 diet involves eating normally for five days of the week, and then restricting your calorie intake to 500-600 calories on the other two days of the week. And while it doesn’t specifically list out the hours in which you can and cannot eat, consuming only 500-600 calories a day will strictly limit the amount of time you spend eating, so the fasting here happens naturally.

The eat-stop-eat method involves a 24-hour fast once or twice a week. So for example, if you eat lunch at noon on Monday, you can eat regularly until noon on Tuesday. Then, you won’t eat for 24 hours (until noon on Wednesday). This method takes lots of self-discipline, and was designed to promote weight loss and overall health.

So, when can I start?

As with any diet, talk to your doctor before getting started. He or she may have some advice on which plan to pursue, and whether or not it’s right for you. Happy intermittent fasting!


Gunnars, Kris. (2017, June 4.) What is Intermittent Fasting? Explained in Human Terms.

Young, Allison. (2018, January 11.) 6 Things That Happened When I Tried Intermittent Fasting For a Week.

Stipp, David. (2013, January 1.) How Intermittent Fasting Might Help You Live a Longer and Healthier Life.

Copyright 2021