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Diet and exercise for breast cancer patients

A randomised phase II trial of intermittent energy restriction and resistance exercise in women receiving chemotherapy for advanced breast cancer (B-AHEAD3).

Cancer types
Breast cancer
Trial phase


ACF donation
Estimated trial cost

Why this trial

Research has shown that energy restriction and weight control protect normal cells from the effects of chemotherapy whilst increasing the sensitivity of cancer cells to treatment - the so-called ‘differential stress response’. Many breast cancer patients are above an ideal weight and many patients gain fat and lose muscle during chemotherapy.

Too much fat and reduced lean body mass (fat-free body mass) have increased chemotherapy toxicity and poorer outcome. Weight loss is therefore recommended in breast cancer patients who are overweight.

The benefits of losing weight by diet have not been fully investigated in women with advanced breast cancer. This study was designed to assess the value of dietary restriction with respect to the effectiveness of chemotherapy to halt progression of the disease and the reduction of side effects.

If successful, this approach could have been widely used to help women with advanced breast cancer and possibly other cancers in the future.

Why this intervention

The main aim of dietary intervention is to reduce energy intake. Studies in animals indicate that energy restriction, mainly achieved by reduced carbohydrate intake, is associated with reduced tumour growth and progression.

In the trial outlined here, the approach used is intermittent energy restriction (IER). Previous studies suggest this may be the best way to achieve weight loss. Previous randomised trials in women without breast cancer indicate that IER is associated with greater weight loss, preservation of fat-free mass and other benefits, compared with standard continuous energy restriction (CER). The researchers developed an IER diet that involves two consecutive days of severe energy restriction and five days of normal healthy eating.

Trial design

In this randomised trial, 134 women receiving chemotherapy treatment for advanced breast cancer were planned to be assigned to one of two treatment groups. The women were recruited by 10 centres in the UK.

The first group (control group) would consist of 67 patients. Patients in this group received chemotherapy and followed a regular diet while taking part in resistance training three times a week.

The second group (the intervention group) was also planned to consist of 67 patients. The patients in this group followed the 5/2 diet whilst receiving chemotherapy. During restricted diet days, these patients were allowed a maximum caloric intake of 800 to 1000 kcal and 50 g of carbohydrates per day. The other five days, they followed a Mediterranean diet. This includes eating lots of fruits and vegetables, nuts, fish, low-fat dairy products, white meat and limited quantities of red meat. Patients also participated in resistance training 3 times per week.

The trial tested whether an energy restricted diet adds to the anti-tumour effect and lessens chemotherapy toxicity compared to a resistance exercise-only intervention.



The trial was terminated in 2021 because of several issues impeding the recruitment of patients.

Results are expected to be published in Q2 2024.



  • Dr. Michelle Harvie, Genesis Breast Cancer Prevention Centre, Manchester University NHS Foundation Trust, Manchester, UK (Principal Investigator)
  • Dr. Sacha Howell, University of Manchester and The Department of Medical Oncology, Manchester, UK


  • Manchester University NHS Foundation Trust, Manchester, UK

Our role

Financial support

Why we support this trial

Intervention has little or no commercial value

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Expected survival benefit

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No major hurdle for clinical implementation

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ACF donation
Estimated trial cost

Questions about participation?

Michelle Harvie
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Questions about this trial?

The Anticancer Fund
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More info on Cancer Reseach UK: B-AHEAD3

Chlebowski, R.T., et al. (2006). Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women's Intervention Nutrition Study. J Natl Cancer Inst, 98(24):1767-76. doi:10.1093/jnci/djj494

Del Fabbro, E., et al. (2012). The relationship between body composition and response to neoadjuvant chemotherapy in women with operable breast cancer. The Oncologist 17(10):1240-5. doi: 10.1634/theoncologist.2012-0169

De Lorenzo, M.S., et al. (2011). Caloric restriction reduces growth of mammary tumors and metastases. Carcinogenesis, 32(9):1381-7. doi: 10.1093/carcin/bgr107

Harvie, M., et al. (2013). The effect of intermittent energy and carbohydrate restriction v. daily energy restriction on weight loss and metabolic disease risk markers in overweight women. The British Journal of Nutrition, 110(8), 1534-47. doi:10.1017/S0007114513000792

Lee, C., et al. (2012). Fasting Cycles Retard Growth of Tumors and Sensitize a Range of Cancer Cell Types to Chemotherapy. Science Translational Medicine, 4(124), 124ra27. doi:10.1126/scitranslmed.3003293

Author: Kristine Beckers (Trial Manager)

Last updated: March 2024.