Last year, I learned about Dr. Michael Mosley’s research on diet and exercise through his wonderful PBS series. I was surprised by the things he was talking about, fasting and exercising minimally but intensely, all based in scientific medical research.

Since watching his show, I have been paying more attention to fasting and the scientific evidence for it seems to grow by the day. I decided to read Dr. Mosley’s book, The Fast Diet: Lose Weight, Stay Healthy and Live Longer with the Simple Secret of Intermittent Fasting to see what it could add to my knowledge.

If you haven’t heard anything about fasting, the basic theory behind it is that the human body is designed to function best with occasional periods of minimal eating. Some theorize that the body spends a lot of its energy digesting food and that when you deprive yourself of calories occasionally, in addition to burning fat and promoting weight loss, you allow the body to take on higher level functions like repairing damaged cells.

Fasting is also the least expensive form of dieting and accessible to anyone with the willpower, regardless of income level.

Dr. Mosley indicates that scientists are still researching the benefits of fasting and that there are many theories as to how to fast. Some advocate constant caloric restriction or eating only during an 8 hour period each day. One researcher is experimenting with every-other-day fasting as a weight loss tool. Some say fasting should occur less frequently (say once per month) but last 3-5 days at a time. Research is still ongoing as to how long you have to fast before the body kicks into cell repair mode (and it may vary from person to person).

Dr. Moseley’s book advocates a “5-2” eating pattern every week, that is, eat normally for five days and restrict your calories two days. The two days can be consecutive (if you can stand it) or spread out throughout the week. On calorie restriction days, women can have up to 500 calories and men 600 calories. Ideally, you eat this all in one meal and spend most of your time fasting but Dr. Moseley and Ms. Spencer indicate that they found it worked best for them to spread the calories throughout the day and they each do it slightly differently.

They answer questions like “Will I get headaches?” “Should I worry about low blood sugar?”and “What to Eat.” Michael gives perspective on how the diet works for men and Mimi the female perspective. The last half of the book gives recipes, a calorie counter and testimonials from various people about how the diet worked for them.

Note that the book indicates this diet is not to be followed by pregnant women, Type 1 diabetics, children under 18 and anyone suffering from an eating disorder. As with any diet, checking with your doctor first is always a good idea.

This book is a great, easy read reference for anyone new to fasting. I didn’t find the scientific section quite as compelling as Dr. Moseley’s television series but it did cover most of the main points and added a few new ones as well. The addition of the female perspective from Ms. Spencer was wonderful but I wished there was more of it. The recipes and calorie counter pages were not all that helpful to me but would be great for someone who is new to dieting in general.

The two parts of this book that are the most helpful are the scientific research overview and the testimonials from Dr. Moseley, Ms. Spencer and others. When I need a refresher on fasting or need some motivation, this is a great book to pull.

Would you (or have you) tried fasting? Please share your thoughts in the comments.

In my next post . . . the medical evidence so far for fasting.