The relationship between alcohol consumption and insulin resistance shows a U-shaped curve: insulin resistance is minimal in individuals with regular mild to moderate alcohol consumption and increases in both heavy drinkers and subjects without any alcohol consumption. These favourable metabolic effects on insulin sensitivity of moderate alcohol consumption may explain the significant reduction in the development of type 2 diabetes and the risk of cardiovascular complications reported in numerous epidemiological studies. This latter effect has also reported in patients with diabetes mellitus, although this observation remains controversial. However, alcohol consumption could increase the global risk of hypoglycaemia, both in the fasting state and after a meal (reactive hypoglycaemia) in both diabetic and nondiabetic subjects. These latter effects may result from a direct inhibition of gluconeogenesis, from a reduced secretion of counterregulatory hormones and/or from an alcohol-induced inappropriate behaviour.