Experts believe more than 14,000 women a year would probably not develop the disease if they adopted healthier behavior from an early age. They believe that modern lifestyles which lack exercise, and include high levels of artifical, processed food, which have caused increased obesity, are fuelling the rise of the disease, as reported at the European breast cancer Conference recently.

One of the researchers estimated that 25 to 30 per cent of cases could be avoided if women were thinner and did more exercise.

But it was not clear if already overweight women could lower their cancer risk by slimming down or if long-term damage had already been done.

Research shows that obese women are almost 50 per cent more likely to die from breast cancer than women carrying fewer pounds. Possible explanations are that changes in hormone levels triggered by weight gain could be behind estrogen-dependent tumors, which form the majority of cases.

The World cancer Research Fund last year suggested up to 40 per cent of diagnosed women - around 18,000 a year - could avoid cancer by adopting a healthier lifestyle.

They reviewed 954 separate studies and concluded that:

"The evidence is now convincing that drinking alcohol, being physically inactive and having excess body fat all increase risk of breast cancer,"

"There is also convincing evidence that breastfeeding reduces the mother's risk of breast cancer. Overall, we estimate about 40 per cent of breast cancer cases in the UK could be prevented through these lifestyle factors."