28th April 2013
I’ve written about the 2 Day Diet before (see below) and I promised to write a review; somewhat belatedly, here it is.
I think Michelle and Tony Howell have done a great job. There are lots of books out there based on some variation of intermittent fasting, but this is one of the few that is actually written by two people who genuinely know what they are talking about. The book is based on research they have been carrying out for many years at the Genesis Breast Cancer Prevention project based in Manchester. As the name implies the emphasis is on intermittent energy restriction for 2 days, while encouraging people to eat a healthy Mediterranean diet for the other 5 days. They suggest that the two days should be back to back, for a variety of reasons.
Firstly they think that if people do them back to back they are more likely to actually do them.
Secondly “it may have additional health benefits”. The reasoning is that if you do your fast days back to back you are spending more time in a better metabolic state. As they point out, “levels of insulin and leptin fall quickly (within 24 hours) when we eat less, so cells can put more effort into staying in top condition”.
I suspect that many people find it easier to split the fast days; that is certainly what most people who contact me say. I would be very interested to see a trial comparing back to back with split days eg Mondays and Thursdays. I have had a lot of contact from people whose blood glucose and cholesterol levels have improved markedly using the split day method.
In addition to the science, “how to do it” and recipes, there is lots of sensible advice on exercise. I think it is well worth a read and I wish their research all the best
An interesting variant on intermittent fasting is something called the 2 Day Diet, based on research by Dr Michelle Harvie and Professor Tony Howell. You will be hearing a lot more about this as they have a book out soon and the book is being serialised next week in the Daily Mail. It is also given a lot of support in today’s Daily Mail by Jenni Murray
Dr Harvie is a leading research dietician and Tony Howell is professor of medical oncology at the University of Manchester; he is also research director of Genesis Breast Cancer Prevention based in Manchester.
Their primary motivation is finding ways to reduce the risk of breast cancer and I have written about their research in The Fast Diet.
Their most recent study was a randomised trial at the beginning of last year, the results of which have been sent off for publication to a nutrition journal. In it they did a three way randomisation of 115 women comparing a daily energy restricted Mediterranean style diet (ie a standard diet) to two different versions of the 5:2 diet.
The first version of the 5:2 diet involved eating 650 calories a day for two days; on those days the women had to cut out pasta, bread, potatoes and all fatty foods. The diet consists mainly of milk and vegetables. For the other five days a week they could eat as much as they liked, although encouraged to eat healthy foods.
Women on the second version of the 5:2 diet were banned from eating carbohydrates for two days of the week but they did not have a specific calorie limit. A sort-of modified Atkins approach.
The third group followed a standard weight-loss diet, sticking to about 1,500 calories a day and avoiding high-fat foods and alcohol.
The striking finding was that after three months the women on either of the 5:2 diets had lost an average of nine pounds (four kilos) – nearly twice as much as those on the standard diet, who lost just five pounds (2.4 kilos). They were also almost twice as likely to have stuck to their diet.
As I mentioned above, they have a book out called The 2 Day Diet which I look forward to reading. It provides considerable further support to research showing that intermittent fasting offers benefits over and above standard dietary advice.
I’ve been in email chat with Dr Harvie, who generously praised my “excellent” Horizon. “The fact that you did it and showed it worked was, to us, very powerful television. We see intermittent dieting as another approach that people may wish to use but it clearly does not suit everyone. However it could have considerable public health importance and that is why we wrote our book, the proceeds of which will go to the charity Genesis who support our work.”
I will write a review when they send me a copy. I will also keep you up to date with further developments. Exciting times…..