Obesity has a prevalence of approximately 10% among Dutch adults. It is a chronic, incurable disease with a high mortality and co-morbidity. The co-morbidity can be reduced significantly by a sustained moderate weight loss (5-15%). The main cause of obesity is an imbalance between energy intake and energy expenditure. The primary treatment combines dietary education, behaviour modification and increased physical activity, followed by pharmacotherapy or surgery when necessary. Obesity is related to several aspects of oral health, such as caries, periodontitis and xerostomia. In addition, obesity may have implications for dental treatment.