The primary objective is to evaluate taste preferences for alcohol during an intravenous infusion of the naturally occurring hormone fibroblast growth factor-21 (FGF21) and placebo (i.e. saline), respectively, in 20 healthy subjects. Secondary endpoints are to evaluate the effects of exogenous FGF21 (compared to placebo) on resting energy expenditure, preference for salt, sour and bitter taste qualities, sensations of hunger, thirst, appetite, satiety, headache and nausea, and makers of glucose metabolism (e.g. plasma/serum concentrations of glucose, C-peptide, insulin and glucagon).

Inclusion Criteria:

• Informed consent
• Caucasian male
• Body mass index between 19 and 27 kg/m2
• Normal haemoglobin and normal glycated haemoglobin A1c (HbA1c) (< 42 mmol/mol)
• Weekly alcohol intake of less than 14 units of alcohol (1 unit = 12 g ethanol)

Exclusion Criteria:

• Liver diseases evaluated by plasma alanine aminotransferase (ALAT) > 3 × normal level or an International Normalized Ratio (INR) below normal values
• Diabetes mellitus
• Nephropathy
• First-degree relatives with diabetes and/or liver diseases and/or alcohol use disorder
• Other diseases the investigator finds disruptive for participation in the study

Individual participant data will not be available to other researchers.