Does alcohol cause weight gain? It can, since it supplies a lot of calories. If you simply add alcoholic beverages to your diet, rather than drink them in place of other caloric beverages, all things being equal, you’ll gain weight. What’s more, if you’re trying to watch your calorie intake, alcohol can make you less focused on how much you’re eating (this is called disinhibition), so you may overeat. Thus, many diets advise limiting alcoholic beverages.
Research on alcohol and weight has yielded inconsistent findings. Statistics show that, on average, drinkers are no more likely to be obese than nondrinkers. But many variables are involved, including the amount of alcohol consumed, the type of beverage, the timing, setting and pattern of consumption, and physiological and psychological factors.
As far as pure alcohol goes, one gram supplies nearly twice as many calories as a gram of carbohydrates or protein (7 vs. 4). But alcohol calories may be different than other calories, according to some research, in that they are burned less efficiently—meaning that calories from alcohol are, in effect, a little less “fattening” than calories from carbs or fat.
Gender may also play a role in how alcohol affects weight. A Harvard study in the Archives of Internal Medicine in 2010, for instance, found that normal-weight women who had one or two drinks a day gained less weight over a 13-year period than nondrinkers. The researchers noted that, unlike men, women tend to substitute alcohol for other beverages or foods.
In May a study in the American Journal of Clinical Nutrition provided another angle on gender differences. It compared the food and calorie intake of a nationwide sampling of 1,864 people on days when they did and didn’t drink alcohol. On the drinking day, the men consumed 433 extra calories, on average, 363 of which came from the alcoholic beverages, the rest from extra foods and other beverages. (These averages include the 10 percent who were heavy drinkers, which skews the numbers higher.) The men consumed more protein, fat, sodium and meat on the drinking day.
In contrast, women consumed an extra 299 calories, on average, on the drinking day, with almost all of them coming from the alcoholic beverages. They didn’t eat significantly more food than on the nondrinking day, though they also tended to eat more fat and less healthfully.
The study looked at isolated days and said nothing about changes in body weight or long-term dietary patterns. But it does highlight the nutritional and caloric dangers of booze.