What's the least fattening alcohol? Im starting to get fat, but I like to drink

Weed is not an option unless I want to fail a drug test and become unemployed.

I read somewhere straight Vodka, or maybe Whiskey with ice is the way to go. I don't remember which.

I drink beer maybe twice a year - usually it's cheap box wine as my poison of choice.

When I say fat, I mean I just had to buy a new pair of jeans and I'm thinking I might be starting to grow moobs.

Any advice? My metabolism isn't that fast, and I'm physically impaired due to a birth condition, so even walking for exercise is kinda torture.

And no, I will not contemplate giving up booze.