Alcohol is notorious for leading people to overeat because of its physiological effect on appetite and because it is generally consumed in a social setting where food is plentiful. There is no place to store alcohol in our bodies the way we do food; therefore the body must preferentially use incoming alcohol as its energy source in order to keep it from reaching toxic levels.
This gives alcohol its natural ability to stimulate appetite by depleting your glycogen (carbohydrate) stores in order to metabolize it, causing you to begin to crave carbohydrates. Alcohol also acts like a diuretic, increasing urination thus decreasing electrolytes like sodium. Again, we now begin to crave the things we are losing, hence our desire for salty carbohydrate-like foods (e.g. chips, dips, crackers, etc.). When you combine alcohol's natural effects on appetite with its well known un-inhibiting effects at a destination full of palatable foods, you have hungry people who often end up with no cares about what and how much food they consume.