 The current study is an open-label single arm prospective design, including 24 healthy young lean males BMI between 18 and 25 kgm2, of whom 12 Dutch South Asians and 12 Dutch Caucasians. After a medical screening, included subjects will receive 12 weeks of treatment with the GLP-1 analogue exenatide Bydureon; 2 mg s.c. 1xwk. Study subjects will visit the LUMC weekly. Before and after treatment there will be a study day, in which BAT by means of 18F-FDG PET-CT scan and MRI scan, resting energy expenditure measured by indirect calorimetry and fat mass by bio-impedance analysis will be measured. Moreover, blood will be drawn to investigate the effects of exenatide on lipid- and glucose metabolism. 