Effect and Safety of Semaglutide 2.4 mg Once-weekly on Weight Management in Subjects With Overweight or Obesity.

This study will look at the change in body weight from the start to the end of the study. The purpose of the study is to compare the effect on body weight in people taking semaglutide (a new medicine) and people taking "dummy" medicine. In addition to taking the medicine participants will have talks with study staff about healthy food choices, how to be more physically active and what else they can do to lose weight. Participants will either get semaglutide or "dummy medicine" - which treatment is decided by chance. Participants will need to take 1 injection once a week. The study medicine is injected with a thin needle in a skinfold in the stomach, thigh or upper arm.• The study will last for about 1 year. Participants will have 11 clinic visits and 8 phone calls with the study doctor. Participants will have 3 clinic visits where they cannot eat and drink (water is allowed) for up to 8 hours before the visit and 1 clinic visit where they cannot eat and drink for up to 2 hours before the visit. (4 visits and 1 visit, respectively, if they have type 2 diabetes (T2D)). Participants will have 4 clinic visits where they will have blood samples taken. (5 visits if they have T2D). For China: Participants will have 9 clinic visits where they will have blood samples taken. Women cannot take part if pregnant, breast-feeding or planning to become pregnant during the study period.