Michael Mosley is a medical journalist who was interested in various forms of diet regimes. He went around the world researching various weight loss options and made a documentary for the BBC about his findings. His book The Fast Diet came out of the work for the documentary.
This diet, sometimes referred to as the 5:2 diet, the two day diet or the fast diet, has been subjected to a number of scientific trials and there appears to be evidence for the benefits of intermittent fasting.
Although the book is called The Fast Diet, it is not about fasting as such. You are not expected to do without food in any way, during the two days you have a reduced food intake.
Likewise, on the other five days, you should not be eating absolutely anything you want, or else you are unlikely to lose weight or get the benefits of the diet, as your weekly calorie intake will not be much reduced.
Rather on the five days, you should eat a normal but not excessive amount of food.
What you are doing with the Fast Diet is reducing your overall calorie intake over the course of a week.
By sticking to the diet there is the potential to create a calorie deficit of around 3000 calories, which equates to around a pound of body fat.
So you can see it is not fasting in any way. But rather a reduced calorie intake.
It’s quite possible to have 3 small meals a day on 600 calories, or 2 more reasonably sized meals. Maybe try scrambled eggs in the morning with a little ham.
In the evening, maybe a lot of vegetables with some fish or chicken. Trying to have as much volume of food without it containing may calories will be key to you not feeling overly hungry on these days.
In general, lots of vegetables and proteins will be good. But try to avoid obvious carbs and fatty foods on the two diet days.
The fact that you are only really dieting two days a week with The Fast Diet certainly makes it more psychologically attractive as there is not same same perpetual everyday slog as there is with standard diets.
Even from a nutritional standpoint, this is a really sensible diet, especially compared to some of the diets people try.
As long as you try to balance your food intake to make sure you are still getting your vitamins and minerals, calcium, etc on the fast days, there should be no negative nutritional effect.
Try your best to get your dairy produce included like milk, yoghurt or cheese to get your calcium.