Women have been warned that yo-yo dieting can more than double the risk of developing kidney cancer. Scientists have found that women who repeatedly lose weight only to put it back on are at a significantly higher risk of the disease later in life. Experts have known for years that smoking and obesity are two of the main risk factors for kidney cancer. But the latest research suggests that "weight cycling" - as typified by the fluctuating shape of Geri Halliwell - may exert an even bigger influence on the disease than body size. Each year 6,700 people in Britain are diagnosed with kidney cancer, most over 65 and more men than women. It is the UK's 13th most common cause of cancer and is notoriously difficult to treat.

Swedish and American scientists studied 140,057 women aged between 50 and 79 for almost eight years, and found that yo-yo dieting and a large waistline were far bigger risk factors in the development of the disease in older women than just obesity. Women whose weight fluctuated by more than 4.5kg (10lb) on more than ten occasions during their adult life were two and a half times more likely to develop kidney cancer than women whose weight had remained stable. The researchers also found it was safer for women to gain weight steadily as they grew older than to lose weight and keep it that way through strict dieting. Women who did this were found to have a 60 per cent increased risk of developing the cancer.