The aim of this trial is to investigate the potential of liraglutide to induce and maintain weight loss in overweight or obese subjects with type 2 diabetes. Treatment will be added onto subject's pre-trial background diabetes treatment of either diet and exercise only or single compound oral antidiabetic drug (OAD) treatment (metformin, sulphonylurea [SU] or glitazone) or combination OAD treatment (metformin, sulphonylurea or glitazone). The duration of the trial will be 56 weeks followed by a 12 week observational follow-up period.