I don't think replacing the pasta sauce with something else will help much,unless if your really worried about the small amount of calories in the sauce compared to the huge amount of calories in pasta. Unless you are eating a special low GI pasta, the pasta sauce is just as bad as the pasta when dieting, maybe worse. I would replace it with nothing or Psylium husks to avoid any extra calories, but probably won't make much of a difference considering the huge amount in pasta, though.