Going to bed too soon after eating may increase the risk of breast cancer recurrence, a study suggests.
A short "night fast" of less than 13 hours led to a 36 per cent greater chance of tumours returning in women treated for early-stage breast cancer.
Scientists collected data on 2413 women with early breast cancer who participated in the Women's Healthy Eating and Living study, which looked at the effects of diet on women's health.
Over an average period of 7.3 years, waiting less than 13 hours before breakfast was associated with a 36 per cent higher risk of breast cancer occurrence compared with fasting for longer.
The women taking part, who were aged 27 to 70 at diagnosis, fasted for an average of 12.5 hours per night.
Shorter fasting was not linked to a higher risk of dying from breast cancer or any other cause.
The US authors, led by Dr Ruth Patterson, from the University of California, San Diego, wrote in the journal JAMA Oncology: "Our study introduces a novel dietary intervention strategy and indicates that prolonging the length of the nightly fasting interval could be a simple and feasible strategy to reduce breast cancer recurrence.
"We hypothesise that interventions to prolong the nightly fasting interval could potentially reduce the risk of Type 2 diabetes, cardiovascular disease and other cancers. Thus, findings from this study have broad and significant implications for public health."
Dr Richard Berks, from the charity Breast Cancer Now, said while the research is intriguing, more research is needed before recommendations can filter down to patients.
"What we do know is that women can reduce the risk of their breast cancer coming back by maintaining a healthy weight," he said.
