Obesity is a complex condition. In addition to conservative measures, bariatric surgical interventions are available for treatment. The number of bariatric procedures in Germany is increasing annually. A bariatric surgical procedure must be supported in an interdisciplinary manner. Alongside intensive medical care, behavioral and exercise training, as well as nutritional counseling and dietary therapy, are essential components in the care of patients undergoing bariatric surgery. In the German-speaking world, a guideline was first developed in 2011, which is now presented in an updated, expanded, and revised version that not only focuses on dietary therapy and nutritional counseling but also unites various interdisciplinary specialties. In this edition, existing chapters have been thoroughly revised to address psychological aspects.