In fact, women drinkers had significantly lower body weight than nondrinkers. As alcohol intake among men increased, their body weight decreased. Although moderate doses of alcohol added to the diets of lean men and women do not seem to lead to weight gain, some studies have reported weight gain when alcohol is added to the diets of overweight persons. When chronic heavy drinkers substitute alcohol for carbohydrates in their diets, they lose weight and weigh less than their nondrinking counterparts. Furthermore, when chronic heavy drinkers add alcohol to an otherwise normal diet, they do not gain weight.
Alcohol metabolism alters the balance of reproductive hormones in men and women.
In men, alcohol metabolism contributes to testicular injury and impairs testosterone synthesis and sperm production. In a study of normal healthy men who received 220 grams of alcohol daily for 4 weeks, testosterone levels declined after only 5 days and continued to fall throughout the study period. Prolonged testosterone deficiency may contribute to feminization in males, for example, breast enlargement. In addition, alcohol may interfere with normal sperm structure and movement by inhibiting the metabolism of vitamin A, which is essential for sperm development. A study of the effect of alcohol on estradiol levels in postmenopausal women found that in women wearing estradiol skin patches, acute alcohol consumption significantly elevated estradiol levels over the short term.