NHS 70 research discoveries: 2-Day Diet helps reduce breast cancer risk through weight loss

In the seven week run-up to the 70th birthday of the NHS, we will highlight a different research discovery from Manchester University NHS Foundation Trust each week from the past 70 years. 

Week 5 – 2-Day Diet helps reduce breast cancer risk through weight loss

In 2013 researchers from the Prevent Breast Cancer Research Unit at Wythenshawe Hospital and The University of Manchester published a new diet that they believed was a real breakthrough in both people losing weight and keeping it off and helping lower the risk of breast cancer and other weight related diseases.

Major international studies have confirmed that being overweight or obese increases the risk of 13 cancers. The World Health Organisation now says that being overweight and obesity are the most important known avoidable causes of cancer after tobacco.  

Dr Michelle Harvie Research Dietitian at Wythenshawe Hospital began researching optimum diet and exercise strategies to prevent breast cancer and its recurrence in 2001. Alongside Tony Howell Professor of Medical Oncology, she was one of the first to demonstrate that weight loss can reduce risk of breast cancer.

Continuing her work in this area and collaborating with Tony, they set out to develop an easy-to-follow diet that people were likely to stick to and trialled an intermittent diet approach to help reduce a person’s risk of breast cancer.


Their work led to the creation of the 2-Day Diet, a simple concept that sees two consecutive days of a reduced calorie intake followed by five days of a “normal” healthy eating that offers an acceptable balance between excess and abstinence. Relieved of the psychological pressure of maintaining a daily diet, more women found it easier to develop healthier eating habits, lose weight and keep it off. The 2-Day Diet seemed to retrain their appetite and often gave people more energy.

To validate the diet, researchers at the Nightingale Centre examined the changes that occur in the breast when women follow either an intermittent (2-Day Diet) or daily diet. Results showed that women could achieve and maintain weight loss and reductions in hormone levels linked to cancer risk by simply changing to this healthier diet and lifestyle plan.

The team looked at changes in breast cells over 1 month in 23 women following the diet. Women not only lost on average 8-9 pounds, but just over half of the women had important changes in their breast cells which indicated the cells were more stable and behaving in a way which would make them less likely to become cancerous.

The diet was tested in 126 overweight women in the breast screening programme and showed that 6 out of 10 women who started on the diet managed to lose > 5% of their weight and keep it off after one year which is highly successful.

The group’s current project the Family History Lifestyle study is testing whether they can support people to follow the 2 Day Diet using an interactive phone and web site. This could be used in a number of settings in the NHS where weight loss is required.

Since launching the 2-Day Diet book has sold 350,000 copies in 18 different copies, with all author proceeds going to Genesis Breast Cancer Prevention.

Read further publications on this work: