This session introduces the topic of obesity and its role in type 2 diabetes: why we are so prone to become obese and what may drive the current obesity pandemic, and hormonal regulation of body weight. The session further discusses how obesity is a major cause of type 2 diabetes, current paradigms explaining the molecular link, aging and diabetes, and the clash between diabetes and COVID-19 involving inflammation. The session ends with a discussion on lessons from the past on how we have failed to control obesity, and what we must do now and in future to prevent obesity and type 2 diabetes.