Frequent consumption of french fries by girls aged three to five increases the risk of breast cancer once they grow up, while the consumption of whole milk at this age slightly decreases the risk, according to a report by researchers at Brigham and Women's Hospital and Harvard Medical School in Thursday's issue of the International Journal of Cancer. The researchers conducted a case-control study involving 582 women who had breast cancer and 1,569 controls who did not. They were selected from among participants in two major Nurses Health Studies. "These data suggest a possible association between diet before puberty and the subsequent risk of breast," they wrote, noting that information about the diets was obtained from the mothers of the participants with a 30-item food-frequency questionnaire. "Differential recall of preschool diet by the mothers of cases and controls has to be considered as a possible explanation for the observed associations," they wrote. "Further studies are needed to evaluate whether the association between preschool diet and breast cancer is reproducible in prospective data not subject to recall bias," they added. Israel Cancer Association chairman Prof. Eliezer Robinson said the results "strengthen previous knowledge proving that diet has a deciding influence on the development of cancer, and that obesity causes a variety of cancers such as colon, breast, prostate and kidney." He added that in recent decades, with the growth in consumption of "junk food" such as french fries, hamburgers, hot dogs and of other high-fat foods, the cancer rate has gone up. According to the World Health Organization, 35 percent of all cancers are due to high-fat diets and being overweight. Children should be taught from a young age to exercise regularly, eat lots of fruits and vegetables, limit their consumption of fried and burnt foods and prefer canola, olive oil and tehina to other oils and fats, Robinson said.