BY DR MICHAEL MOSLEY

when the body stops burning sugar and starts burning fat.

In the Fast 800 there are three stages: Rapid Weight Loss (or the ‘Very Fast 800’), then the New 5:2 and finally Maintenance.

It’s up to you how long you stay doing the first two, and it will depend how much weight you want to lose and how easy you find them to stick to.

RAPID WEIGHT LOSS

For this stage, you eat only 800 calories a day – not just for two days a week but every day for a minimum of two weeks.

You can safely stay at this stage for anything up to 12 weeks, particularly if you want to really kick-start your diet or have to lose weight rapidly because of type 2 diabetes or a fatty liver. This stage is so effective that it’s possible to lose up to a stone in just three weeks. I also recommend adding in a Time Restricted Eating (TRE) programme, aiming to have a 12-hour overnight fast each day.

This has several benefits. It imposes discipline and, because you’re having all your calories in a relatively narrow window, it stops you constantly thinking about your next meal. It also increases the opportunity for fat-burning ketosis.

Use the recipes in this booklet to make up your 800 calories – they’re designed to be filling as well as nutrient-rich. Or you could use mealreplacement shakes (from last week’s YOU).

Because the recipes are low-carb as well as low-calorie, after a few days your body should switch from burning sugar to burning fat, which will also help suppress your appetite. You may get headaches or become light-headed during this stage, possibly because of dehydration, but these feelings will pass. If you stick to this stage for a month, you can expect to lose 20 lb, or 30 lb after eight weeks, most of which will be fat.

THE NEW 5:2

Once you’ve kick-started your weight loss with the Very Fast 800, you’ll be on a roll and it’s entirely up to you when you move on to the next stage, the New 5:2.

For some people a couple of weeks’ rapid weight loss is enough. Others will want to stay at stage one for longer, depending on goals.

Either way your hunger and cravings should be very much reduced. You should be feeling lighter, brighter and more energetic, and people will be commenting on how well you’re looking.

When you go on to the New 5:2, you’ll experience a more gradual weight loss.