Does Alcohol Cause Weight Gain? It’s Complicated.

“How much alcohol do you consume?” This is a standard question asked of someone seeking weight-loss support. The question is often followed up with a short talk about the caloric content of alcoholic beverages—especially those containing sugar, syrups, cream, and fruits marinated in syrup—and how those calories can inhibit weight loss. Moreover, the dieter’s answers to the question might also explain some of the reasons why he or she gained weight. Perhaps the cause was eating too much bar food; Buffalo wings, peanuts, chips, and chunks of salami and cheese, in addition to a few beers, can add pounds. Did the dieter perceive that having a drink or two before a meal might make her less inclined to exhibit restraint over how much or what she ate? Further probing might have revealed another effect of alcohol intake: disturbed sleep. Frequent awakenings during the night may follow even moderate alcohol intake and cause subsequent daytime fatigue. Did overeating during the day in a futile attempt to counteract the fatigue lead to excessive calorie intake? And was having a drink after work an excuse for not going to the gym or at least taking a walk?

And yet should alcohol consumption be viewed as a significant contributor to weight gain and obesity, or is the situation more complicated?

The answer is: It depends. Obviously the caloric content of alcohol—7.1 calories per gram—can do much caloric damage after a weekend of heavy drinking or a long afternoon spent on a boat drinking beer. According to a review by Traverse and Chaput, heavy drinking can be a source of unnecessary and excessive calorie intake. But the relationship is not clear. While we may regard a beer belly as the consequence of too many afternoons on the boat or in the bar, there is no consistent evidence of a relationship between alcohol intake and BMI (body mass index) in women and men. What seems to be possibly related to weight gain is the amount of alcohol consumed over a short period of time. Thus, one or two glasses of wine with dinner over a week are less likely to be related to weight gain, but drinking the equivalent of 14 glasses of wine on a Saturday night may be.

If the drinker compensates for the calories in alcohol by decreasing calorie intake from food, this would explain the lack of weight change with moderate drinking. But again, the evidence is not clear. In several studies, volunteers were given, unknown to them, either an alcoholic beverage or a similarly tasting but alcohol-free beverage before a meal and then allowed to eat what they wished. The volunteers ate the same amount of food each time; the effect of ingesting calories in the alcohol beverage had no effect on how much they ate subsequently. This is one reason why those on a diet are warned that the calories in a cocktail or two before dinner would not decrease their appetite. The alcohol calories (like the cost of the cocktails) would be added to the total calories from the meal.

Some researchers have suggested that alcohol consumption may remove the control the eater has over what he is consuming. But other factors may come into play: If drinking is being done in a celebratory setting, or enticing snacks are available to make the drinker thirsty and thus likely to drink more, or the individual is not paying attention to what he is eating at a reception with passed appetizers and an open buffet. It is unlikely that the drinker will be focusing on the number of calories from the alcohol he is consuming and making a conscious decision to eat less food as a consequence. So hypothetically, enough such occasions could result in weight gain.

However, according to some of the studies referenced in the Traversy and Chaput article, lifestyle, rather than alcohol per se, may promote weight gain. Replacing a brisk walk with watching a game, drinking beer, and eating nachos drenched in melted cheese may promote weight gain, but the alcohol may be only one of the factors responsible. Conversely, people often decrease their alcohol intake along with sugar and fat-rich foods when they start a weight-loss or exercise program, not just because of caloric considerations, but because it makes them feel better.

Moreover, whether a dieter should be able to manage moderate alcohol consumption depends on its contribution to their daily calorie intake. It is hard to stay on even a moderately low-calorie diet and eat enough protein, carbohydrates, fruit, vegetables, and dairy products to meet one's daily nutrient needs. And if the dieter wishes to add some high-fat foods like cheese, salad dressing, butter, or olive oil to their daily food intake, the calorie count goes up rapidly. If additional calories from alcohol are ingested, then daily calorie intake may be just high enough to slow weight loss, especially if the dieter is sedentary.

Eliminating or reducing alcohol consumption is a common dieting behavior. Less well known, and indeed potentially harmful to the health of the dieter, is eliminating food almost entirely in order to consume alcohol. According to the National Eating Disorders Association, some individuals may suffer both from anorexia and an alcohol use disorder. They often drink rather than eat, believing that alcohol consumption will suppress their appetite. Moreover, in order to compensate for the calories ingested from alcohol, these individuals will starve themselves. This is unofficially known as drunkorexia.

A less extreme version of substituting alcohol for food when attempting to lose weight is to eliminate carbohydrates from one's diet, and to consume wine instead. Several years ago we had dinner with an acquaintance who refused to take any bread from the breadbasket because he was on a diet, and lectured us on the evils of carbohydrates. “I prefer to drink my calories," he told us, pointing to the bottle of red wine he had ordered. This he did—by consuming the entire bottle.

So what should you do about alcohol consumption while on a diet? A common-sense approach is to drink very moderately, if consuming a very small amount of alcohol will make staying on the diet easier. And exercise might compensate for the extra calories so weight loss won’t be slowed. But if the alcohol leads you down a slippery slope to munching on cheese-drenched nachos and Buffalo wings, stick to club soda and a slice of lime.