Hi, it's antiquated logic that alcohol metabolizes into sugar. I know you said your class was 20 years ago, so I'm not surprised that was the teaching. The reality is that most people see a drop in their glucose levels after drinking alcohol. Alcohol is broken down in the liver into acetate - which is then broken down further into CO2 and water.
To the OP... the bottom line is that excess calories make you fat. It may sound simplistic, but it's far more accurate than to think of it in terms of fats, sugars, etc. Avoiding excess sugars and alcohols will help you maintain your um, figure, by helping to curb your calorie consumption. You could avoid all the fat and sugar in the world and if you consume so much protein that you are in excess of your daily calorie needs, you'll get fatter. Sugars are carbohydrates and carbohydrates contain 4 calories per gram. Alcohol is the forgotten macro nutrient and actually contains 7 calories per gram. The calorie composition of the beer you drink will reflect this, the residual sugars and alcohol will contain those calories. In addition to simple calorie consumption, alcohol and sugars have affects on fat mobilization and your metabolism in general, but it's honestly simple enough to think of your consumption in terms of daily calories unless you are an alcoholic or consume inordinate amounts of sugars on a daily basis, in which case you have other more serious problems.
Oh and yea, carbohydrates will raise your glucose levels. Sugars are carbohydrates. In fact, liquid sources of carbohydrate will raise your glucose levels faster than solids - IE, juice is faster than bread.