How to do intermittent fasting safely

Fasting for weight loss can be effective, but you need to do it safely. Here's what you should know first.

Caroline Roberts Digital Editorial Intern
Caroline Roberts writes articles and notifications for CNET. She studies English at Cal Poly, and loves philosophy, Karl the Fog and a strong cup of black coffee.
Caroline Roberts
3 min read

Fasting for weight loss can be effective, but you need to do it safely.

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You've probably heard of intermittent fasting, the popular diet that involves restricting the hours during which you can eat. It's heralded as a weight loss method, and research suggests that it can also boost your immune system, cure high blood pressure and more.

Intermittent fasting is well-known, but it's only the tip of the iceberg when it comes to fasting diets in general. There's practically infinite ways you can adopt a fasting regime that suits your own lifestyle and health needs. Let's take a look at all the different fasting diets, the health benefits they may bring and how to do them safely.

Read more: The health risks of intermittent fasting: It's not for everyone

Five common fasting methods

Fasting is essentially not eating food for a defined amount of time. Civilizations around the world have incorporated fasting into their religious and cultural lives for thousands of years, but it's recently grown popular as a way to possibly lose weight and experience other health benefits. 

You can modify a fasting diet in any way it works for you, but here are some of the most common patterns:

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Usually when people fast, the only things they consume during the fasting period is plain black coffee, tea and water -- you can even put a dash of salt in the water for electrolytes. However, a lot of people believe that consuming anything under 50 calories will keep you in a fasted state, so you could throw a dash of heavy cream or oil in your coffee to help tide you over.

What are the benefits of fasting?

There's a lot of preliminary research on fasting that points to some pretty promising benefits, but many more studies are needed to back up the claims.

One major benefit of fasting is that it helps promote autophagy -- a process in which your cells essentially "take out the trash" by removing dysfunctional components. Increased autophagy can possibly regenerate the immune system and increase your cell's protection against stress. 

Some research suggests that fasting can also lower blood pressure, as well as making your body more sensitive to insulin. Being more insulin-sensitive means that you'll store energy from food more efficiently, and get less hungry between meals.

Now to the main reason people try fasting -- to lose weight. While one study showed that both fasting and caloric restriction (eating less throughout the day) had the same weight loss results, losing weight is a highly individual journey. If you've been struggling to find a way of eating that helps you be your best self, you may want to give fasting a try.

Who should try fasting?


People with diabetes shouldn't fast, at least not without consulting a doctor first.

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Fasting is not recommended for people with chronic health issues, especially anyone with diabetes or gout. Medical professionals also discourage fasting for people who are underweight or have experienced disordered eating in the past.

However, if you're in good condition and want an alternate way to lose weight or are interested in the benefits of autophagy, you may want to give fasting a try. Or, if you already feel sluggish after eating a meal upon waking up, you could try out an intermittent fasting schedule that better suits your needs.

Still, you should always talk to your doctor before starting a fasting diet -- they'll know how to help you approach it in the safest way possible.  

When should you stop fasting?

Generally, if you feel bad enough during a fast to the point where it's impacting your daily life, you should highly consider stopping.

Besides that, there are some sure fire signs that you should break your fast. If you notice yourself feeling extra dizzy, confused, light-headed or are having trouble concentrating, get some nutrients and calories in your body. Binge eating after your fast ends is another sign that you're falling into some emotionally unhealthy behaviors.

If you've been fasting for more than just a few hours, start slow with the re-feeding -- try to sip on light soup or something easily digestible like crackers before you attack a full meal.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.