A convincing body of data supports that excess body fat and depression are strongly linked. To tease out whether being overweight causes depression through social influences, like discrimination, or via physiological pathways, like elevated blood pressure or elevated blood sugar, scientists conducted a series of sophisticated genetic studies using data from the UK Biobank. The Biobank includes genetic profiles and detailed mental health data on more than 145,000 study subjects. 

The results? Both social AND physiological factors occurring in individuals who are overweight can cause depression. The lead scientist commented that the study provides “the most robust evidence to date that higher BMI causes depression.”

Human Molecular Genetics, 2021; DOI: 10.1093/hmg/ddab204