Eating and drinking too much can be deadly, says a new medical study which directly links excess consumption to breast cancer. Undertaken by UNSW Sydney, the research claims that body fatness and alcohol intake are the leading preventable causes of the disease in Australian women, which remains the most common cancer in women worldwide. The news is especially a cause for concern considering that more than half of Australian women have admitted to regularly drinking and with three in five either overweight or obese.

The study determined its findings with data collected from 200,000 women around the country as a part of a collaborative study led by UNSW’s Centre for Big Data Research in Health. It combined six Australian cohort studies, specifically evaluating what proportion of pre-menopausal and post-menopausal breast cancers could be prevented by changing lifestyle behaviours.

The key? Simply keeping weight and alcohol consumption down says the study. It’s believed doing so will help to prevent thousands of breast cancer cases. “We found that current levels of overweight and obesity are responsible for the largest proportion of preventable future breast cancers – more specifically, 17,500 or 13 per cent of breast cancers in the next decade,” says study author Dr Maarit Laaksonen.

“Regular alcohol consumption is the second largest contributor – 13 per cent of pre-menopausal and 6 per cent of post-menopausal breast cancers, that is 11,600 cases over the next 10 years, are attributable to consuming alcohol regularly.”

This was the first time that regular alcohol consumption was shown as a leading preventable cause of breast cancer, with the study revealing that risk of breast cancer increases with the average consumption of just one drink per day.

The other leading preventable causes for breast cancer were determined to be hormone-related, namely menopausal hormone therapy (MHT) contributing to 7 per cent of breast cancers, and long-term use of oral contraceptives contributing to another 7 per cent. Jointly, these behavioural and hormonal factors cause one in five breast cancers or 37,000 expected breast cancers in the next decade.

But it’s not all bad news with the findings becoming an important way in helping to target and prevent the development of preventable cancer around the globe. “Even relatively small preventable proportions translate into large numbers of preventable breast cancers,” Dr Laaksonen explains. “If confirmed, these findings are likely to contribute important evidence for individual and population-level cancer control strategies.”