Here’s the latest diet craze: The Fast Diet – also known as the 5-2 Diet. It’s the hottest-selling diet book in the UK. It’s been #1 on Amazon for 3 months, and it just came out here. The diet is based on the premise of intermittent fasting – where you eat what you want 5 days a week – and almost nothing for the other two days. On “fast days,” you eat about 500 calories total. 

The diet was created by Dr. Michael Mosley, a medical journalist for the BBC. He based the diet on several fasting tests – mostly done on mice – that led to weight loss, increased energy, and lower risk of cancer and heart disease. And when he tested it on himself, he lost 20 pounds in about 9 weeks. He also reduced his glucose and cholesterol levels, and the amount of dangerous belly fat.

He says the diet works because when we fast, the body begins to turn off your fat-storing systems, and turn on the fat-burning ones. 

Dr. Mosley also points out that our early ancestors lived a feast-or-famine existence, gorging after a big hunt and then not eating again until they scored the next kill. 

But plenty of nutritionists say it’s just another crazy fad diet. And it’s downright dangerous. 

Zoe Harcombe, author of The Obesity Epidemic, believes going on an intermittent starvation-diet could trigger eating disorders in people prone to them.

And “the Fast Diet” is so popular, Britain’s National Health Service felt the need to address it on their website, saying fasting diets can lead to bad breath, anxiety, constipation, dehydration and irritability. They also said there are huge gaps in the book’s scientific evidence. 

Bottom line: If you want to lose weight, you’re a lot better off eating a healthy diet, every day.