Sugar and calories in alcohol

Maybe im too drunk, but i cant understand or find out how much sugar and calories alcohol have. I googled jack daniels suagr content and saw this: ”Jack Daniel’s Black Label Tennessee Whiskey has no carbohydrates (sugar or starch), gluten, fats, or cholesterol, as these are removed in the distilling process. One fluid ounce of Jack Daniel’s contains approximately 65 calories. ”

Where does the calories come from then? Does it really not contain any sugar? Also how much sugar does tequila contain generalyy?