Women who cut their calorie intake for two days a week could reduce their risk of breast cancer, a study has found.
Researchers claim the 5:2 diet, as it’s most commonly known – can lead to cancer-preventing changes in the breast tissue.
The diet involves two days a week on a low-carb, low-calorie diet, with the remaining five days being spent on a healthy, Mediterranean-style diet.
One theory is that when the body is deprived of food the amount of sugar reaching breast cells decreases, which may result in them dividing less frequently and turning cancerous.
The diet was devised by Dr Michelle Harvie, a research dietitian at the breast cancer charity Genesis, and lead author of this study.
The small study – entitled Breast Risk Reduction Intermittent Diet Evaluation (BRRIDE) – saw overweight pre-menopausal women at high risk of breast cancer follow The 2-Day Diet for one month.
Researchers took breast biopsies on 20 women before and after the four-week trial.
On average, women lost around half a stone in weight, with 55 per cent of those taking part experiencing changes in their breast cells, it is claimed.
Such changes involve the production of proteins that are known to make the cells more stable and less likely to become damaged.
Therefore, the risk of developing breast cancer is reduced, the study authors report in the journal Breast Cancer Research.
Dr Harvie, who is based at the Nightingale and Genesis Prevention Centre in Manchester, said: ‘We know weight loss can reduce the risk of diseases such as breast cancer.
‘However, people often find sticking to a continuous low-calorie diet difficult and can “fall off the wagon”, so to speak, very quickly.’
She explained until now, it was unclear what effect an intermittent diet had on the breast itself.
Not was it known what changes, if any, take place when following such a plan.
Dr Harvie added: ‘While the study used a relatively small sample size, all participants were monitored very closely, with regular check-ups and consultations taking place so we knew they were definitely following the diet.’
But she cautioned further research was needed to confirm how the diet could prevent breast cancer.
She added: ‘There are a number of reasons why some of the women didn’t experience changes in the breast; for example, they may have needed to spend a longer period of time on the diet or perhaps follow a different version of The 2-Day Diet.’
The study is part of Genesis’ wider research programme looking into how diet and lifestyle changes can reduce the risk of developing breast cancer.
It is hoped that the findings will encourage more women to take up the diet – and stick to it.
Dr Harvie, who also operates from the University of Manchester and collaborated with the University of Edinburgh for the study, added: ‘Many of our patients often struggle to understand how the diet can benefit them and reduce risk of breast cancer developing, or returning in some cases.
‘Now, the results from BRRIDE mean we can tell them what is likely to be happening in the breast cells and how their diet could have a potentially life-saving effect.’
Commenting on the research, Eluned Hughes, of the charity Breast Cancer Now, said: ‘Whether women at high risk of breast cancer could reduce their chances of developing the disease through diet is an interesting question, but this early study is too small to suggest that the 5:2 diet might be the best approach.
‘That said, lifestyle and diet is a fascinating area of research.
‘Overall, up to a third of breast cancers could be prevented through healthy lifestyle changes – such as maintaining a healthy weight, being physically active and reducing your alcohol intake.
‘We need to continue to find practical and everyday ways to help women reduce their breast cancer risk.’