Researchers say you can add weight control to the ever-growing list of potential health benefits that come from drinking a single glass of red wine.

Although alcohol contains calories, research has suggested again and again that those calories don't necessarily contribute to weight gain. In fact, a Harvard University study published in a March 2010 issue of the Archives of Internal Medicine that looked at more than 19,000 normal-weight women over the age of 38 found that those who consume light to moderate amounts of alcohol are in better shape than those who drink heavily or abstain altogether.

Moderate consumption is generally defined by health experts as no more than one drink a day for women and no more than two a day for men. "One drink" is equal to 12 ounces of regular beer, 5 ounces of red or white wine, 1 1/2 ounces of spirits (80 proof) or a 10-ounce wine cooler or spritzer.

Red wine is of particular interest to researchers because it has a high antioxidant content that singles it out from other alcoholic beverages and potentially puts it in the category of a healthful food. One of the first indications that red wine consumption has little or no effect on weight gain came in 1997, when researchers at Colorado State University specifically looked at the effect of red wine on body weight in a small group of healthy men. They found no difference in weight when the men drank two glasses of red wine with dinner every day for six weeks than when they drank no alcohol and consumed the same number of calories from food.

The researchers could only speculate as to how and why red wine, and possibly other alcoholic beverages, may play a role weight control. In more recent years, animal studies performed in universities around the world have pointed to the antioxidant resveratrol, which is found in particularly high amounts in red wine and red grapes, and which has long been thought to provide some protection against the development of heart disease and other diseases associated with aging. Resveratrol is now thought to also help neutralize the effects of fat in the diet and boost the metabolism to burn calories more efficiently.

Just like any other overindulgence, however, too much red wine or other alcohol can contribute not only to weight gain but to chronic medical conditions, such as liver disease, heart disease, gastrointestinal disorders and neurological problems. And if you're thnking about saving up your daily alcohol calories for a weekend binge, think again. According to experts at the University of Illinois's McKinley Health Center, the benefits of moderate drinking only apply when you stick to a daily limit.

Archives of Internal Medicine

Colorado State University: Researchers Find No Link Between Moderate Red Wine Consumption and Weight Gain

Potsdam University: Alcohol, Calories & Weight

University of Illinois/McKinley Health Center: Alcohol and Nutrition 101

Science Daily: Resveratrol Studies