Low carb diets go in and out of fashion for weight loss, and according to new research, it suggests that an occasional low carb day is better than traditional diets for helping to prevent breast cancer.

The findings are set to be presented at the San Antonio Breast Cancer Symposium.

Reducing both insulin levels and weight are known to help prevent breast cancer. But dietary changes are hard to stick to. The research, led by Michelle Harvie, compared three diets over a four month period for their effects on weight loss and blood markers of breast cancer risk.

They gave patients either a calorie-restricted, low-carb diet for two days of the week, an "ad lib" low-carb diets where they were allowed unlimited protein and healthy fats for two days a week, or a calorie-restricted "Mediterranean diet" for seven days a week.

Intermittent dieters produced greater effects than the constant one, with a mean weight loss of 4kg per person, compared to 2.4 kg on the "Mediterranean diet".