Scientists may have found a reason why some women have a tendancy to put on weight very easily, the BBC reports this week. They have found that obese women convert excess dietary carbohydrate to fat faster than lean women. This process is known technically as de novo lipogenesis. Researchers from the Scottish Agricultural College in Ayr and the Medical Research Council in Cambridge tested the response of lean and obese women to two types of diet. The first was rich in carbohydrates, but designed to provide just enough energy to meet each woman's daily requirements. The second was loaded with excess carbohydrates, and designed to provide 50% more energy than the women actually needed. When the volunteers were fed on the energy-balanced diet, the rate of de novo lipogenesis among the obese women was nearly twice that among the lean women. Women who had a high rate of de novo lipogenesis in response to the energy-balanced diet also had a high rate when given the energy-loaded diet. The researchers say their results suggest that some individuals may have an intrinsically higher, perhaps genetic, potential for de novo lipogenesis. Full findings are published in the current issue of the American Journal of Clinical Nutrition.