​Nutrition The 2 day diet

Friday 04 May 2018

This week I wanted to write a blog on the article that ran last week in the Daily Mail newspaper on the new 2 day diet. I have been asked a great deal about this and some of you may have seen it in the paper. The book that the extracts in the Mail were taken from has been published this week and is now available in the shops.

Some of you may remember a blog I did a little while ago on the Michael Mosley 2:5 diet. Well this follows a similar principle but slightly different in its approach. It was written by Dr. Michelle Harvey and Professor Tony Howell who both work at the Manchester Oncology clinic with ladies with breast cancer. Michelle Harvey is a dietician specializing in optimum diet, weight loss and preventing cancer and its recurrence. Tony Howell is a Professor of Medical Oncology who specialises in treating breast cancer and is research director of Genesis Breast Cancer Prevention. They have both written many research papers so have quite a pedigree between them.

The publication of their diet came about after 7 years of trials. They were so impressed with the results that they decided to go public. Hence the book and the Mail articles.

What is the new  2 day diet?
The principles behind the diet are driven by encouraging weight loss as they observed that many women who go through treatment for breast cancer tend to gain weight. This is not unsimilar to the principles behind Michael Mosley's book as he focussed on weight loss also. They both focus on doing this by creating a reduction of insulin growth factor, which seems to be the key to successful and sustained weight loss.

So why is this so important? Well naturally babies and young children have high levels of growth factor needed for their growth and development. As we reach adulthood and our growth slows down and stops so our levels of the natural growth factor decline because we do not need it anymore. However the way that we tend to eat these days encourages an increase in growth factor which as the name implies stimulating cells to grow. Obviously not ideal.

The main food culprits that increase levels of this growth factor appear to be sugars and simple or refined carbohydrates in our diet. When we eat these types of foods our levels of the hormone insulin go up. The role of insulin is to carry the excess sugar from our blood into our cells where it is used as energy or stored as fat. This of course can create one problem, potential weight gain.

The other is that when insulin levels are raised this stimulates the production of growth factor. I did a blog on this at the beginning of the year explaining all about insulin growth factor or IGF-1 which you may like to look at.

The 2 restricted days on the 2:5 diet helps to achieve a 40% reduction in insulin than a standard calorie reduced diet. This is one of the fundamental benefits of the 2 day diet which unsurprisingly is naturally low in sugary carbohydrate type foods (the sugars and refined grains).It is also thought that by having the 2 restricted days it puts the healthy cells in the body into repair mode rather than go go mode. Unlike Michael Moseley this diet specifies very clearly how the 2 day diet should be structured and which foods should be included. The idea of this structure is to make sure that the 2 days of restricted eating are balanced nutritionally. Michael Moseley does not specify which foods to eat other than to keep to the calorie restriction. Harvey also suggests that the diet should also be done on 2 consecutive days for maximum benefit.

On each of the 2 restricted days you can eat.

  • Protein foods (chicken, fish, eggs, lean meat) a maximum of 12 servings a day. One serving weighs approximately 1 ½ - 2oz depending on the type.
  • Dairy 3 servings a day. 1 serving is equivalent to ½ pint of milk or alternatives which he lists.
  • 1 serving of fruit only, with the understanding that fruit does contain sugar in the form of fructose.
  • 5 servings of vegetables, each serving should weigh 2 ½ oz (80grms).
  • A maximum of 5 servings of fats a day. Each portion measured in teaspoons or table spoons depending on the type.

You will notice that the diet is heavily in favour of protein foods. This is because protein foods keep us satisfied longer and so will not (or should not in theory) get as hungry as quickly. Also protein foods have been shown to help stabilize fluctuations in blood sugar levels. It is also vital to help retain muscle mass when you are dieting. He also suggests that protein foods burn an extra 65-70 calories to absorb and digest them.

The BRIDE (Breast Risk Reduction Intermittent Diet Evaluation) study has analysed breast tissue to see if the diet has made any changes to how the genes are behaving. The hope is that the 2 day diet may reduce the activity of the CSD gene which is thought to be a factor in the development of breast cancer. Research is on going.

My observations of this diet are;

That if you are used to eating a high proportion of vegetables then there are not many on this diet.

It includes dairy foods which does surprise me in the light that dairy itself contains growth factor and also oestrogen which is found naturally in milk. I would love to know their thinking behind this.

In his selection of fat choices he includes the non beneficial processed fats (hydrogenated and trans) as well as the more beneficial essential fats found in nuts and avocados. Interestingly there is no mention of seeds which as we know are a good source of essential fats like omega 3.

I think that if you like structure and being told what to eat then it is a good diet to adopt but in my food selection I would try to have the healthier options from the options. i.e. avoid the margarine and mayonnaise and choose the olive oil or unsalted nuts.

The book is full of extracts from people who have followed the diet and how well they have done. There is also a section of questions and answers to clarify any points that people may be confused about. The back section of the book is full of recipes and menu ideas to help with the structure of the days and also some instruction of how to manage the non restricted days. So quite comprehensive. If you are struggling with weight and want a fresh approach that has been well researched tried and tested than it may be for you.

It is interesting to note that exercise seems to have a similar beneficial effect on reducing insulin levels. This would make sense because the sugar that is carried from the blood into the cells by insulin will be used as energy rather than be stored as fat.


Blog originally written by Caroline February 2013

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