Oatmeal is a slower-digesting carb than pure sugar, yes, but after it goes through your gut it's broken down into pure glucose, which inevitable ends up in the bloodstream. Fiber is good for you, yes, and I never said that oatmeal was bad in and of itself. However, I personally wouldn't add any sugar since all of the carb in it (aside from the fiber) will still get converted to sugar in the body eventually.
The only reason complex carbs are said to be good for you is because of all the vitamins and minerals and fiber they come along with in the foods in which they are found. If you extracted the complex carbs out of the oats, yams, beans, etc., and ate them alone, they would be no better for you than table sugar or potato starch.
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).