BACKGROUND: Rodent studies have highlighted the possibility that alcohol may promote a significant decrease in the level of glucose-stimulated plasma insulin concentration. The aim of this study was to investigate whether a similar alcohol-induced decrease in plasma insulin occurs in humans, by assessing the level of plasma insulin and plasma glucose when a moderate amount of commercially available bottled white wine is consumed alone after a meal. METHODS: Eight nondiabetic men aged 19 to 22 years participated in this investigation. Participants were required to consume some food for 45 min before ingesting three standard units of white wine (30 g of alcohol) over 90 min. Plasma insulin and plasma glucose levels were assessed at regular 45-min intervals across the experimental period. RESULTS: The data showed a significant alcohol-induced decrease in the level of plasma insulin and a nonsignificant trend for a decrease in plasma glucose concentration in all participants after 15 g of alcohol had been consumed alone after a meal. CONCLUSIONS: These findings highlight the possibility that white wine, if consumed alone after a meal, may significantly alter energy utilization and possibly cause an alteration in glucose metabolism.