It sounds so saintly. After Yuletide boozing, give up alcohol for just 31 days and see the benefits pour in. Television ads, social media posts, even promotional texts from food and drink brands now push the perks of so-called Dry January. You’ll save money, they say. You’ll drink less the rest of the year. You’ll just love their brand new non-alcoholic mocktails (which are, somehow, close in price to standard cocktails). Most important: Your health will improve.