The aim in the present study was to assess the effect of small-moderate red wine ingestion on the level of serum insulin and plasma glucose when nutritional status is varied. Twenty nondiabetic males (19-22 years) participated in the study. In the fasting trial, all participants underwent a 6 h fast prior to consuming 4 standard units of red wine (40 g alcohol) or the equivalent amount of placebo as dealcoholized wine (containing <0.5% alcohol, 0% resveratrol) over a 135 min period. Alternatively, in the feeding trial, participants consumed food for 45 min prior to ingesting 4 standard units of red wine (40 g alcohol) or placebo over 135 min. Serum insulin and plasma glucose were assessed at regular 45 min intervals during all trials. The results showed a significant decrease in the level of serum insulin and no significant change in plasma glucose concentration in the fasting trial. Alternatively, a significant alcohol-induced decrease in plasma glucose and no change in serum insulin occurred when red wine alone was consumed after food. It was concluded that red wine can alter the glucose-insulin relationship and ingesting red wine alone (without food) should not be encouraged in nondiabetic individuals.