The prevalence of obesity is increasing rapidly both globally and in Finland. Obesity poses a significant risk for many diseases such as type 2 diabetes, coronary heart disease, stroke, and several cancer types. The obesity-related complications develop through complex interactions between genetic and environmental factors, and their manifestations vary remarkably between individuals. The factors responsible for these variations are difficult to disentangle in humans and the predictors of long-term health are poorly understood. In Obesity Research Unit we study the pathogenesis and treatments for obesity and related metabolic complications, with a particular focus on the role of mitochondria. Researchers in Obesity Research Unit have various collaborations both nationally and internationally.