A very little bit of sugar that's in a pinch isn't any kind of a problem. Even a tbsp isn't that much. The problem is the massive amount they put in drinks of all types...and foods of all types. They even put it in bread for heck's sakes.
In terms of taking the edge off of tomato sauce, shredded carrots works pretty well. I don't use sugar in any of my cooking, and no one has noticed.