Normal-weight women who drink a light to moderate amount of alcohol appear to gain less weight and have a lower risk of becoming overweight and obese than non-drinkers, according to a report in the March 8 issue of Archives of Internal Medicine.
More than half of American adults drink alcoholic beverages, according to background information in the article. Alcohol contains about 7 calories per gram and alcohol drinking may possibly lead to weight gain through an imbalance of energy consumed and energy burned. However, research has not consistently provided evidence that consuming alcohol is a risk factor for obesity.
Lu Wang, M.D., Ph.D., of Brigham and Women’s Hospital, Boston, and colleagues studied 19,220 U.S. women age 39 or older who had a body mass index (BMI) in the range classified as normal (18.5 to 25). The participants were free of cardiovascular disease, cancer, and diabetes mellitus and had a baseline body mass index within the normal range of 18.5 to less than 25. Alcoholic beverage consumption was reported on a baseline questionnaire. Body weight was self-reported on baseline and 8 annual follow-up questionnaires.
On an initial questionnaire, participants reported how many alcoholic beverages they typically drank per day. A total of 7,346 (38.2 %) reported drinking no alcohol; 6,312 (32.8 %) drank less than 5 grams; 3,865 (20.1 %) drank 5 to less than 15 grams; 1,129 (5.9 %) drank 15 to less than 30 grams; and 568 (3 %) drank 30 grams per day or more.
Over an average of 13 years of follow-up, women on average gained weight progressively. Women who did not drink alcohol at all gained the most weight, with weight gain decreasing as alcohol intake increased. A total of 7,942 (41.3 %) women who initially had normal weight become overweight or obese (BMI of 25 or higher), including 732 (3.8 %) who become obese (BMI of 30 or higher). Compared with women who did not drink at all, those who consumed some but less than 40 grams per day of alcohol were less likely to become overweight or obese. Women who drank 15 to less than 30 grams per day had the lowest risk, which was almost 30 % lower than that of non-drinkers. The associations were similar by subgroups of age, smoking status, physical activity level, and baseline BMI. The authors conclude that compared with nondrinkers, initially normal- weight women who consumed a light to moderate amount of alcohol gained less weight and had a lower risk of becoming overweight and/or obese during 12.9 years of follow up.
“An inverse association between alcohol intake and risk of becoming overweight or obese was noted for all four types of alcoholic beverages [red wine, white wine, beer and spirits], with the strongest association found for red wine and a weak yet significant association for white wine after multivariate adjustment,” the authors write.
Professor R. Curtis Ellison comments: In a very well-done and complete analysis, these investigators found that normal-weight women who consumed alcohol had considerably lower risk of becoming overweight or obese over 12.9 years of follow up than did non-drinkers. There was a step-wise decrease in risk from about 5 grams/day up to 30 grams/day,. Among the strengths of this study were that the women were all health professionals, which should minimise the strong effects of income and social class on alcohol intake and body size, that all of the women had a normal BMI at baseline and that very similar results were seen regardless of initial BMI, smoking status, age, and level of physical activity.
Multivariate-adjusted mean body weight change in kilograms during 12.9 years of follow up are shown in Figure 1 from the paper for subjects aged (A) < 50 years, (B) 50-59 years, and (C) aged 60 or older at baseline.
While the differences by alcohol intake were greater in the two younger groups (A & B), the patterns were similar and statistically significant in all age groups. As seen in the figure, subjects with at least 5 grams/day of alcohol had persistently lower weight gain than subjects who did not consume alcohol. There was little difference between nondrinkers and those reporting > 1 to < 5 grams of alcohol/day.
A weakness of the study is that the pattern of drinking was not known for the women. Hence, effects for regular drinkers who consumed alcohol on most days of the week cannot be separated from those of binge drinkers. And while only the baseline consumption of alcohol was used in these analyses, alcohol intake that was updated from assessments on two later occasions in this study were tested as a time-dependent variable, and the authors state that these analyses gave similar results.
In multivariate analysis, the authors adjusted for many factors that relate to alcohol intake and/or body size. These included age, race, baseline BMI, non-alcohol energy intake, physical activity level, smoking habits, postmenopausal status, postmenopausal hormone use, multi-vitamin use, history of hypercholesterolemia and hypertension, and dietary factors including intake of fruit and vegetables, whole grains, refined grains, red meats and poultry, low-fat dairy products, high-fat dairy products, energy-adjusted total fat, carbohydrates, and fiber. For each person who became overweight or obese, time-of-event was calculated as the estimated time when her BMI crossed the cutoff point through regression modeling. Further, their sub-group analyses all gave similar results as their overall results.
The results of this study are similar to more-limited studies of weight change and alcohol among women; these include the Nurses’ Health Study I, the Nurses’ Health Study II, and the National Health and Nutrition Examination surveys. In other reports, similar findings were not seen among Chinese and British males or among Finnish men and women, although specific reasons for these differences are not clear. A number of studies suggest that alcohol may increase body weight in men, perhaps due to greater amounts of alcohol, different drinking patterns, differences in the metabolism of alcohol, or to suggestions from other studies that men tend to add alcohol to their daily dietary intake, whereas female drinkers usually substitute alcohol for other foods without increasing total energy intake. In this study, all of the groups consuming alcohol had higher total energy intake than non-drinkers, but the non-alcohol calories were lower in women consuming 15 or more grams/day of alcohol, due mainly to fewer carbohydrates’.
Source: Wang L, Lee I-M, Manson JE, Buring JE, Sesso HD. Alcohol consumption, weight gain, and risk of becoming overweight in middle-aged and older women. Arch Intern Med. 2010;170(5):453-461