The aim of the study is to evaluate the effect of a caffeine supplement on the stimulation of lipolysis and the production of ketones in healthy adults (N=10). Two different doses of caffeine (2.5 mg/kg of BW and 5 mg/kg of BW) are compared. All the participants have to follow three sequential visits of four hours each, which included a breakfast with one of the doses (2.5 or 5 mg/kg) of the caffeine supplement or without any supplement (baseline) and repeated blood sampling in order to evaluate ketone concentrations.