Not all carbs are created equal. Make sure to read the Atkins book to start. Different carbs turn to gluclose faster then others and can cause a sharper rise in blood sugar and insulin response. If you are using instant oatmeal in the morning with no protien, you are probably starting the day with a massive insulin spike. Look up the Glycemic index which rates carbs on how much they effect blood gluclose. With the higher insulin in your system, any fat eaten will probably be stored.

If you find you can't give up your morning oatmeal, I would sugegst you look at the Zone plan. They encourage balanced eating at each meal and snacks between protien, fat and carbs. Steel cut oats is encouraged for breakfast. Again though that is steel cut oats, the kind that take an hour or so to cook. The more processed a food is, the faster it can enter the blood stream. Instant oatmeals are still a no-no.