There is ample evidence that breast cancer susceptibility is induced during the developmental stages of the human breast where, in a manner related to sex-steroid hormones, insulin plays an important role. In turn, nutrition might be implicated. Regular soft drinks and table beer, both carbohydrate-containing drinks, are candidates affecting insulin concentrations. Eleven teenagers, between the ages of 13 and 17 years, consumed a soft drink and a table beer in a crossover study. The blood levels of insulin and glucose were related to anthropomorphometric and endocrine factors. In contrast to table beer, consumption of regular soft drinks induced a fast and dramatic increase in both glucose and insulin concentration within a maximum 1 hour after consumption. The insulin response was linearly correlated to the body mass index (BMI). Children with a small increase in BMI are highly sensitive to regular soft drinks with regard to glucose and insulin response. The finding suggests a vicious circle of high caloric drinks, increase in BMI and insulin response. It is one of the nutritional pathways which might affect susceptibility for breast cancer in youngsters. Table beer, a drink with fermented sugars, does not share these effects on carbohydrate metabolism.