The weight loss diet loved by Jennifer Aniston, Scarlett Johansson, and Chris Hemsworth

A popular diet that has been around for decades is a favourite among celebrities - and it also lets you eat your favourite foods.

Intermittent fasting is popular among stars like Benedict Cumberbatch, Hugh Jackman, Chris Hemsworth, Jennifer Aniston, Kourtney Kardashian, Halle Berry, Scarlett Johansson and Reese Witherspoon all talk about it.

James Corden even said that he had shed six stone through intermittent fasting, boxing and being mindful about what he ate. He revealed that he boxed nearly every morning and would sometimes only eat an apple at the start of the day. But The Late Late Show host said that he doesn't deprive himself.

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The Gavin and Stacey star said that he doesn’t eat until noon each day and would first drink a 15 calorie, sugar-free vitamin drink. “I have a trainer who I box with most mornings, and so far today I’ve had an apple. I try to eat healthily and not deprive myself," he told The Sun.

But what exactly is intermittent fasting? It's also known as the 16:8 diet which focuses on helping people lose weight by reducing the amount of time they have available to eat.

Here's what you need to know about the 16:8 diet including how it works and the best foods to eat.

The 16:8 diet is a form of intermittent fasting in which you break the day into two periods consisting of 16 hours and eight hours.

Under this diet, people will fast for 16 hours in a day - consuming only things like water, unsweetened soft drinks or drinks without milk - and then consume all their calories for the day during the remaining eight hours.

There are no restrictions regarding the types of amounts of food you can consume during the eight-hour period.

The diet has been designed to work quickly, with the longer fasting period intended to give the body the time it needs to process food and burn away extra fat.

The 16:8 diet works on an hourly basis, which means you eat within an eight-hour time frame and then fast for the remaining 16 hours of the day.

This kind of diet plan helps with weight loss by helping you eat fewer calories and also boosting metabolism. After several hours without food, your body exhausts its sugar reserves and starts burning fat, in a process called "metabolic switching."

This is a natural process, which happens when the body runs out of energy given by food. When this happens, the body starts drawing energy from ketones stored in the fat cells, which helps us lose weight.

The 16:8 diet also helps speed up your metabolism, by causing a rise in a stress hormone called norepinephrine, which makes larger amounts of fat available for your body to burn.

When your metabolic rate is faster, it means you burn calories by doing even basic activities like sitting down, eating and sleeping. However, exercising while intermittent fasting is also encouraged to help build muscle mass.

If you're considering losing weight you should consult a GP, who can give you advice.