Monday, April 7, 2014

Book Review: The Fast Diet By Dr. Michael Mosley and Mimi Spencer

The Fast Diet: The Simple Secret of Intermittent Fasting: Lose Weight, Stay Healthy, Live LongerThe Fast Diet: The Simple Secret of Intermittent Fasting: Lose Weight, Stay Healthy, Live Longer by Michael Mosley
My rating: 3 of 5 stars


The Fast Diet by Dr. Michael Mosley and Mimi Spencer is a small book explaining a method of fasting the authors call the 5-2 diet. This diet consists of eating normally for five days of the week and then restricting calories the remaining two days.  This concept is based on what Dr. Mosley learned in his BBC Horizon documentary Eat, Fast, Live Longer.  He tried different forms of fasting to improve his health and eventually created his own 5-2 approach.

The Fast Diet begins by giving an overview of the science behind fasting and all of its benefits such as helping to prevent cancer, diabetes and depression. This chapter is not very detailed as there needs to be more study on how fasting creates these benefits. Many of the studies have been done on mice and there are not many studies done on humans. So much of the advise in the book comes from what they have seen work in animal studies. Both authors then detail why they decided to start the 5-2 fasting method and the kinds of results they hoped to have.

The second part of the book gives the details of the 5-2 feast/fast program in practice. For two days during a 7 day week a fasting individual would eat 600 calories a day for men and 500 calories a day for women. They stress that during these days you need to eat nutrient dense foods since you will be eating a considerable amount less than normal. They emphasize a plant based diet rich in vegetables and fruit. They recommend for best results that you eat breakfast and dinner. It is more effective for a person to fast for a considerable period of time. For best results they recommend not eating for a least 16 hours.

The third part of the book gives you practical tips for dealing with feelings you most likely will have when starting this program. There is also a large section of frequently asked questions about their 5-2 fasting method. This part is very detailed and one of the most helpful parts of the book. The book then gives sample menus for ten fast days at both calorie levels, plus recipes for the food given in the menus. The food is mostly plant based with a small amount of meat. The fast day food is nutritionally sound and nutrient dense and the recipes are simple and quick to make. The book ends with a collection of case studies and glowing comments. These ending comments seem more like an advertisement for the diet's wonderful benefits rather than an honest overview of people's experiences.

This type of plan seems more sustainable then a continuous fast for 3-4 days. It works because participates will naturally eat less on the other five days. Overall they are eating less than they were before they started the program. The book states that you can eating whatever you want on non fasting days which basically gives the green light to eat processed fast food. There is no science stated in this book that says you are hurting your health by eating junk food most of the time which is a big red flag. Since most of the benefits of fasting have only been seen in mice, it is too early to know if  a diet like this is truly a good idea.

Overall, the book seems more like a fad diet than a health eating plan. Fasting can have benefits but trying to promote the diet by hyping up the "eat whatever you want on the other days" feels like a ploy to sell books.

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