Head Start provides early childhood education to nearly one million low-income children, through federal grants to more than 2,000 local programs. About one-third of children who enter Head Start are overweight or obese. But program directors face difficulty in implementing policies and practices to address obesity—and in our national survey, they identified the key barriers as lack of time, money, and knowledge. Also, parents and staff sometimes shared cultural beliefs that were inconsistent with preventing obesity, such as the belief that heavier children are healthier. Minimizing those barriers will require federal resources to increase staff training and technical assistance, develop staff wellness programs, and provide healthy meals and snacks.