The elusive freshman 15. Brought on by late night Dominos 5-5-5 deal, unlimited dining hall meal plans, and drinking. Lots and lots of drinking. No, the dryer wasn’t shrinking your clothes. But the 30 pack you and your best friend polished off on a thirsty Thursday may have had something to do with your jeans not fitting.
It’s estimated that alcohol contributes to an average of 160 calories a day in subjects of drinking age (1). That’s one glass of wine or for the 21-year-old you – one 10sec keg stand. (How many of those did you do in college? Or at your best friend’s bachelor party?)
As educated readers, you’re aware of the simple formula for gaining weight: consumption in excess of what you need leads to weight gain. The reciprocate is true as well: eating less than your body needs leads to weight loss.
Where does alcohol fit into this equation? Are alcohol consumption and weight loss mutually exclusive?
The addition of excess calories in the form of alcohol naturally has the potential to increase one’s energy intake and therefore lead to weight gain. Allowing alcohol into one’s diet for weight loss (or maintenance) does not suggest finding a magic loophole that allows for shot-gunning beers 5 nights a week as if we’re 21 again.
But, what is exactly is the consequence of a weekend stout or glass of merlot? Can alcohol fit into a healthy diet?
Protein and Carbs energy content is 4 calories per gram; fat 9. Alcohol’s energy content is in between at 7.1 calories per gram. For 1 shot of vodka, that’s approximately 14gm of alcohol. Bare minimum, one shot will cost you 100 calories. Mixed drinks typically include sweetened mixers which can mean at least 15-25gm of alcohol plus the other sugar and carbohydrates; naturally increasing the caloric content.
Unlike the other macronutrients, alcohol cannot be stored for later use and must be utilized immediately after consumption; which leads to the first matter at hand: how is alcohol metabolized?
At low levels of consumption, alcohol is metabolized by the alcohol dehydrogenase system. During alcohol oxidation, hydrogen is transferred from alcohol forming NADH and further oxidized to acetaldehyde. The acetaldehyde is further oxidized into acetate, releasing Co2 and water through the citric acid cycle (1).
The process of creating acetaldehyde leaves a large number of free-floating hydrogen atoms. The presence of so many free hydrogen atoms displaces the hydrogen atoms from fat oxidation and steps in its place for energy metabolism. Simply put alcohol is actually metabolized as a fat (1).
All this time you thought it alcohol was a carbohydrate, right? Don’t worry, you’re not wrong. Most beers are between 5-6% alcohol. That means out of the entire 12 ounce can, only 5% of it is actually alcohol. The remaining 95% is fermented wheat, barley, rye, hops, water, sugar, and a few other things. That 95% is correct to be considered a carb. That small 5% however, steps into the Kreb cycle in place of a fat to be metabolized for use.
Now that the metabolism of alcohol has been established, what role does it play if one is trying to fit into their skinny jeans but still likes an occasional glass of wine or IPA?
Alcohol accounts for approximately 6-10% of the total caloric intake of adults in the US (1). That’s a fairly small percentage considering 48% of the US population consumes 2.6 glasses of soda each day, and liquid sugar is the shortest and quickest path to weight gain. A positive energy balance will result in weight gain, and of course, alcohol has the potential to add calories above energy requirements covered by food.
A large 8-year cohort study examined the long term effects of varied alcohol consumption on the weight over 49,000 nurses aged 27-44; taking into account potential cofounders including dietary patterns, smoking status, genetics, and physical activities. Of the women – 28% stayed within 2.5kg of their baseline weight, 7% lost weight, and 65% gained greater than 2.5kg. (2)
The study found that light and moderate drinkers who consumed 0.1-29.9gm a day, or 2 drinks or less, all had lower mean BMI than non-drinkers even after adjustment for age, smoking, status, physical activity, and menopausal status. In age-adjusted analysis, alcohol intake was significantly inversely related to weight gain. Ex-drinkers, those who gave up drinking mid-study, showed the largest mean weight gain followed by lifetime abstainers. Compared with non-drinkers’ women drinking up to 29.9g/d had lower odds of weight gain.
It sounds surprising to hear that over the course of 8 years, the women who consumed 2 drinks a day or less had the lowest weight gain compared to subjects who never drank. This phenomenon can be attributed to a number of factors one of which is behavior.
Those that consumed light to moderate amounts of alcohol were more likely include alcoholic calories into their existing diet rather than in addition to. Second, alcohol has a greater thermogenic effect than protein, carbohydrates, and fat. That’s certainly not to suggest that drinking burns calories rather, it just takes a little more energy go metabolize alcohol than it would say, a stick of celery.
The thermogenic response of a missed meal is in the range of 12% protein, 8% carbs, and 5% fat. The thermic effect of alcohol on a light to moderate drinker is between 15-25% of the energy content of alcohol intake (2).
An extensive lit review by Sutter examined the effect of alcohol on energy metabolism in healthy young nonalcoholic men consuming weekly alcohol consumption of 2-92gm a week, or 1-7 drinks. The results showed an increased energy expenditure through indirect calorimetry of 3-8% due to alcohol-induced thermogenesis of 14.9-19.3% supporting that alcohol does have a higher thermogenic effect than its macronutrient counterparts (1)
When including age and diet as factors, increased odds of weight gain associated with heavy drinking compared with light to moderate drinking appeared to be more apparent in younger women and in women who consumed higher levels of trans fat. Heavy drinkers showed higher odds of weight gain than light or moderate drinkers and bingeing in short periods had the highest likelihood of gaining weight.
The group least likely to gain weight and have the greatest success at maintaining weight were those who consumed light to moderate amounts of alcohol from 1-3 per day. As for the type of alcohol; wine drinkers showed similar odds of weight gain to beer drinking, but liquor drinkers had the highest odds of weight gain, even despite the level of intoxication (2). When making recommendations to future clients about alcohol choices, beer and wine appear to have the least consequence on the scale.
The role of physical activity plays a role in keeping the weight off as well. A small study by Crouse et al found that only individuals with a heavier body weight status did alcohol led to body weight gain (1). Alcohol consumers on a high-fat diet may experience weight gain more easily than alcohol consumers with a lower dietary fat intake due to the metabolic effects of alcohol on suppressing fat oxidation rate leading to a positive fat balance. (1)
Engaging in regular physical activity, however, may compensate for the positive energy balance that is a consequence of alcohol consumption and aid in maintaining one’s weight. Overall the evidence from these studies suggests that light to moderate drinking is not associated with weight gain in but that heavier levels may enhance weight gain. It’s like saying a cookie or two won’t ruin a diet, but the fall inventory of girl scout thin mints will.
So do alcohol calories count?
Yes, but with high variability from one consumer to the other. The effects of alcohol on body weight depend on the individual consumer’s body weight, diet composition, genetic background, gender, level of physical activity, and family history of obesity.
The research certainly does not suggest alcohol contributes to better health or better performance but knowing the appropriate amount to consume to prevent weight gain certainly can contribute to the freedom of knowing your diet isn’t wasted on a beer for a Sunday night football game. 1-2 drinks here and there has supported evidence that it won’t be catastrophic to one’s weight. The buffalo wings with blue cheese, however…..
Wannamethee SG, Field AE, Colditz GA, Rimm EB. Alcohol Intake and 8-Year Weight Gain in Women: A Prospective Study. Obesity Research. 2004;12(9):1386-1396.
Suter PM, Tremblay A. Is Alcohol Consumption A Risk Factor For Weight Gain And Obesity? Critical Reviews in Clinical Laboratory Sciences. 2005;42(3):197-227.