He is the co-founder of America on the Move, a non-profit organization promoting lifestyle changes to counteract obesity and related health problems, and the National Weight Control Registry, a prospective study of long-term weight loss that was the largest of its kind as of 2018.
His research has primarily focused on the prevention and treatment of obesity and related conditions, such as diabetes and metabolic syndrome.
Hill was a leading force behind the "America on the Move" initiative, a national program aimed at encouraging Americans to make small, sustainable changes to their daily routines, such as walking more and reducing caloric intake, to prevent weight gain and promote healthier living.
He was elected to the National Academy of Medicine in 2014, recognizing his contributions to public health and obesity research.
Hill has authored or co-authored more than 700 scientific articles and book chapters on topics related to obesity, metabolism, and weight management.