They call it a "beer belly" for a reason - although it might not be the reason you think.Conventional wisdom says that alcohol causes weight gain because the calories you drink are stored in the body as fat. In reality though, only 5-percent of what you take in stays in your body. But excessive drinking does lead to weight gain, and that's primarily because the body converts alcohol into acetate. Acetate is actually a source of energy, which your body can use to fuel itself. The problem is that when acetate is being utilized for energy, fat is not - as a result, the fat remains in the body. Therefore, the more alcohol you drink, the more acetate your body will have to burn, and the less stored fat it will use. When your body utilizes acetate as energy, it causes your blood sugar to spike. The resulting blood sugar crash, in turn, makes you ravenous.Add in the fact that alcohol lowers your inhibitions about eating, and you've got a recipe for weight gain disaster. The only real way to prevent this is to drink in moderation, which most define as one or two drinks daily. But, if you're not willing to limit your alcohol intake, at least stick to lighter calorie options. For instance, a 12-ounce beer has about 150 calories, while a 12-ounce light beer has 120. ...and you can swap that 4-ounce margarita for a similarly sized mojito and save yourself 200 calories. Or, just stick to 5-ounce glasses of wine, which have about 100 calories each. These tips can help you to enjoy your alcohol-without ending up with a beer belly.