The short-term effects of moderate alcohol consumption on energy balance, serum lipids, and lipoproteins were studied in eight healthy middle-aged men (age 30 to 47 years and body mass index 23.1 to 27.7 w/h2). A crossover dietary trial included two isocaloric periods without (20% protein, 50% carbohydrate, 30% fat) or with alcohol (12% protein, 29% carbohydrate, 25% fat, 75 g of alcohol as red wine). Each period lasted 2 weeks. The body weight of the subjects remained stable over the study. Fasting blood glucose, serum insulin, total cholesterol, and LDL cholesterol were similar at the end of both dietary periods. Mean values of serum total triglyceride (108 +/- 18 v 85 +/- 24 mg/dL, P less than 0.05), VLDL-Tg (88 +/- 24 v 73 +/- 16 mg/dL, NS), and total HDL cholesterol (49.4 +/- 6.0 v 43.4 +/- 5.5 mg/dL, P less than 0.05) were higher after the diet with alcohol than without alcohol. The increase of HDL cholesterol was primarily due to that of HDL2 cholesterol (10.4 +/- 5.1 v 5.7 +/- 3.9 mg/dL, P less than 0.05). The concentration of apoprotein A-I, A-II, and B averaged 104 +/- 17 v 89 +/- 16 mg/dL, 33 +/- 4 v 28 +/- 8 mg/dL, P less than 0.02, and 111 +/- 24 v 105 +/- 33 mg/dL after the diets with and without alcohol, respectively. Adipose tissue LPL activity increased in six of the eight volunteers during the diet with alcohol. Resting metabolic rate, postprandial energy expenditure, and postprandial responses of blood glucose, serum insulin, triglyceride, and plasma FFA were similar after the both diets.(ABSTRACT TRUNCATED AT 250 WORDS)