You would probably think twice about eating a hot dog, followed by a burger, with a donut for dessert. But drinking 4 pints of 5% cider might not cause you much concern. In fact, you'd be consuming around the same number of calories - around 1000 calories!
Alcohol is seriously fattening.
But it isn't just the calories in the drink that causes weight gain. Alcohol reduces the amount of fat your body burns for energy. Because we can't store alcohol in the body, our systems want to get rid if it as quickly as possible, and this process takes priority over absorbing nutrients and burning fat.
Adding 3 or 4 units per day to your usual diet would lead to an increase in weight of around 4lbs in four weeks.