According to About.com, gin contains no sugar. One jigger—1.5 ounces—has 97 calories, which comes from the alcohol. Gin also has no carbohydrates, protein or fat.
When gin is used with mixers, the sugar content often increases significantly. The Daily Mail indicates a typical gin and tonic has 3 1/2 teaspoons of sugar, which is just over a full tablespoon. The World Health Organization recommends adults limit their sugar intake to no more than 6 teaspoons, or 2 tablespoons, per day. Without taking into account what other foods have been eaten, having two gin and tonics in a single day exceeds the suggested limit.