The investigators plan to include 18 obese/overweight men without diabetes. The primary endpoint of the study is food intake during continuous intravenous infusions of saline (placebo), GIP, GLP-1 and GIP+GLP-1, respectively. Secondary endpoints includes resting energy expenditure (measured by indirect calorimetry), appetite, satiety and hunger assessments (measured by visual analogue scales), plasma insulin, C-peptide and glucagon secretion, plasma triglycerides, cholesterols, and free fatty acid responses and changes in plasma bone turnover markers.