A distilled liquor, gin is made from grain and contains almost pure alcohol following distillation. In order to make gin more drinkable, it is watered down to 40-47% alcohol content and then flavoring is introduced in the form of juniper and assorted herbs. Gin is an English invention of sorts, in response to grain alcohol not tasting very good. In many ways, pure grain alcohol smells like rubbing alcohol and is not very appealing.
Much like the British, we generally drink gin mixed with something else, rather than straight. The most popular of these mixed drinks is the aforementioned gin and tonic, which makes a synergistic pairing of tastes. The problem, for those of us watching our calories, is that tonic has many calories. Six ounces of tonic has approximately 75 calories, which is in addition to the alcohol calories contained in gin.
Adding that to gin, which is a minimum of 65 calories per ounce is going to be one very bad drink for your diet. The exact calories of a gin and tonic will depend on the size of the drink and how large it is and the proportion of gin and tonic. With that said, swapping soda water for tonic will save a considerable number of calories and is an easy substitution, without sacrificing much in terms of flavor.
Another common gin drink is the martini. While there are many different types of martinis, as we see on shows like Mad Men or you will find in a classic cocktail bar, we will discuss two broader types of martinis. The dry martini uses dry gin and dry vermouth. The difference in calories of dry gin and traditional gin is marginal. However, dry vermouth is much less caloric than sweet vermouth, because it contains less residual sugar. If you’re calorie conscious, always opt for the driest vermouth available, typically “extra dry.”
Dirty martinis are similar to dry martinis except there is a significant olive juice component. Olive juice is essentially the marinade that canned olives sit in while on shelves. It makes the martini significantly saltier, similar in sodium content to ocean water. The olive juice also gives the martini a slippery texture and overwhelms the juniper flavoring of gin. If using a less expensive gin, a dirty martini is a good choice.
In terms of calories, the dry martini and dirty martini are quite similar. 2 ounces contain approximately 140 calories and the larger the martini, the more calories. Some bars will even make double martinis and leave the remainder in the shaker. Clearly, there are more total calories, though the alcohol is increased, so you’ll probably drink less of them. Martinis derive almost all of their calories from alcohol, so they are great choices for dieters. If watching your calories, avoid mixers with lots of sugar, such as tonic, and you will do your waistline good.
For more information, read about gin history and gin nutrition