Effects of Fructose/Glucose-rich Diet on Brown Fat in Healthy Subjects (GB7)

A 2 weeks of hypercaloric diet supplemented with fructose or glucose

Acute cold exposure using a water-conditioned cooling suit will be applied from time 0 to 180 min. At the same time mean skin temperature will be measured by 11 thermocouples.

I.v. injection of 18-fluorodeoxyglucose (18FDG) will be performed, followed by 30 min dynamic and 50 min wholebody PET/CT scanning.

i.v. injection of 11C-acetate will be performed, followed by 20 min dynamic PET/CT scanning

i.v. administration of 1.5 uCi/min of \[3-3H\]-glucose

i.v. administration of 0.08 umol/kg/min of \[U-13C\]-palmitate

i.v. administration of 0.05 µmol/kg/min of 2H-glycerol

Visceral and cervico-thoracic MRI and MRS acquisition.

Skeletal muscle activity and shivering intensity will be measured by electromyography using surface electrodes

Lean mass will be determined by dual-energy X-ray absorptiometry

VCO2 will be measured by indirect calorimetry between 15 and 20 min every hour until time 180.