A new study suggests that genetic variation in our ability to digest dietary sucrose may influence our intake and preference for sugary foods. Mutations in the sucrase-isomaltase (SI) gene, which plays a role in breaking down sucrose and maltose, can make it difficult to digest these sugars, leading to a decreased preference for sugary foods. Researchers found that people with a defective SI gene had a much lower preference for sugary foods than those with a functional SI gene. Experiments on mice lacking the SI gene showed a rapid reduction in sugar intake and preference. The findings open the possibility of targeting the gene to reduce sugar consumption.