First off, I've never been on a diet in my life.I've been a vegetarian for 25 years and eat a healthy varied diet with lots of whole grains, vegetables, dried legumes, etc. but since moving to Paris have been eating way too much in the pastry department. Like everyone else reviewing this, I saw the BBC Horizon program "Eat, Fast and Live Longer" (search YouTube - it keeps getting posted there) and was really impressed. This book gives details of the science and recommendations on how to manage the fasting. I've been doing it for a month and feel much lighter and have a better relationship to hunger and portion size. This is a great way to reset and remind your body that less is more. (Dovetails nicely with mindfulness.)My only complaint is that the recipes are all high protein even though in the science section, that's mentioned as being harmful. The reason they give is that for only two days a week, it won't be a problem and that protein helps dull your appetite. Well, whole grains and heaps of steamed veg do that as well and it's a lot healthier.The only thing I didn't like about the book was the section by Ms Spencer -- truly appallingly writing. Read for the info, not the literary merit!