Most simple plain vinegars like Apple Cider, Red Wine and Rice Wine vinegar contain about 0-1 gram of sugar in them (if any) and about 2-5 calories per serving (1 tbsp or 15 grams). You may often see these with 0 sugar listed and 0 calories as they get to round down these numbers on the label.

I have never really worried about these and recommend their use as a salad dressing/condiment. These basic plain vinegars are somewhat tart, do not trigger the pleasure trap and make no significant contribution of calories or sugar.

… often promoted and sold as Flavor Infused Balsamic Vinegars, sometimes as Balsamic Reductions, sometimes as Balsamic Glaze and sometimes as just plain old Balsamic Vinegar. Most of these, if they have a nutrition facts label, will even list 25, 30, 36 or more calories per serving and 7 or even 8 grams of sugar per serving.

These flavor infused balsamic vinegars that are 36 calories per tbsp and have 7-8 grams of sugar are ~1050 calories per pound.

Fruit juice concentrate (which counts as an added sugar) has about 30 calories per tbsp and is ~950 calories per pound

So, these flavor infused balsamic vinegars are slightly more concentrated in calories/sugar then fruit juice concentrate.

Pure maple syrup (which counts as an added sugar) has about 39 calories per tbsp and 9 grams of sugar and is ~1150 calories per pound.

So, these flavor infused balsamic vinegars are slightly less concentrated in calories/sugar then maple syrup, but not by much.

If you mix 14 grams of maple syrup with 1 gram of water, you end up with the exact same amount and concentration of calories/sugar per tbsp as the flavor infused vinegars.

Or, dissolve 1.75 to 2 tsp of sugar in each tbsp of the plain vinegar and you again have the exact same amount and concentration of calories/sugar per tbsp as the flavor infused vinegars.

So, those who are using these higher calorie premium flavor infused balsamic vinegars may not realize they are basically pouring the equivalent of a sugar syrup with a calorie/sugar concentration somewhere between fruit juice concentrate and maple syrup on their food.