Part of the risk is behavioral: Children pick up eating habits from their parents. Also, being exposed to deficits of some nutrients and excess calories in utero—particularly from fats and carbohydrates—can cause changes in gene expression that “trigger all sorts of pathogenic pathways including promoting obesity,” says Dana Dabelea, a professor of epidemiology and pediatrics at the Colorado School of Public Health, Anschutz Medical Campus. These epigenetic changes can affect the development of children’s fat tissue and when they feel full, she says.