In 2012, Dr Michael Mosley introduced the intermittent fasting phenomenon to the world in the form of the 5:2 diet, where you eat 500 calories for two days a week and eat normally (2000 calories) the other five days.
Now, his latest diet program "Fast 800" has gone viral, offering a similar ethos to 5:2, but instead allowing users to eat 800 calories on their two fast days. So we can eat more and still lose weight? Sign us up!
Here, Dr Mosley explains exactly what the diet entails and why it's so darn effective…
Since the launch of the 5:2 diet six years ago, there's been a mountain of research into the benefits of intermittent fasting and calorie curbing and just how beneficial they really are. And because of this, we now know that upping the original 500 calories for two days to 800 has similar results.
"[Eating 800 calories] gave people the same metabolic benefits in terms of weight loss but it's much more doable than the original 5:2," says Dr Mosley.
You can modify the diet to suit your weight-loss needs. For example, if you want to lose more weight quicker, you can begin with the "Rapid Weight Loss" element of the plan. "I've included a component at the beginning for rapid weight loss where a person eats 800 calories a day every day [instead of just two days]," says Dr Mosley.
It's recommended you do rapid weight loss for up to 12 weeks before switching to "The New 5:2" aka "Fast 800", until you reach your goal.
This is when you'll move into the maintenance stage of the diet, whereby you no longer count calories but instead stick to a healthy Mediterranean diet, which we'll delve into some more in a moment!
Another crucial part of this eating plan is knowing when to stop and start eating.
"You simply extend your overnight fast so you eat within an eight or 10-hour window," says Dr Mosley. "So you might stop eating at 8pm and then you don't start eating again until 10 the next morning (10:14)."
While you're in the rapid weight-loss stage, 12 hours of eating and 12 hours of fasting (12:12) is recommended, then for the new 5:2, it's 10:14 or 16:8, and for the maintenance stage it's 12:12 or 10:14.
WATCH: A Q&A with Michael Mosley about his book The Fast 800. Post continues after video...
"One thing I've been making very clear in the last six years since writing the 5:2 is the importance of switching to Mediterranean-style eating," says Dr Mosley.
"People hear Mediterranean diet and they think it's pizza and pasta, but it's not like that at all," he says. "Make sure you're eating plenty of full-fat yoghurt, nuts, oily fish, olive oil, vegetables and fruits."
And the best part? You still get treats! "[You can have] some red wine with your evening meal and a bit of dark chocolate – which is surprisingly high in fibre," adds Dr Mosley.
"The recipes in the Fast 800 have been created to be as yummy and sustainable as possible," he says.
In terms of exercise, Dr Mosley says all that's really needed is three brisk 10-minute walks a day – or any exercise you enjoy to that equivalent.
You can expect to lose two to three kilos in the first week. "In clinical studies of short-term weight loss, they found a loss of 14kg in eight weeks," says Dr Mosley.
Not to mention findings from a UK study that found type 2 diabetes sufferers were able to come off all their medication after following the diet. Amazing!