What do you mean by "Not so fattening"? Are you talking about it being low-fat? "Fattening" really is about having a lot of calories (if you take in more calories than you burn, you will gain weight, so anything high calorie, or even low calorie in large amounts, has the potential to be "fattening").
If you are looking for a low carb breakfast with a fairly high number of calories, you're going to be playing with protein and healthy fat. Protein has 4 calories per gram, and fat has 9 calories per gram, so you can see how adding healthy fats in will help you boost the calories. Nuts would be great, and so would bumping the protein.
What about preparing your oats with protein powder, then topping with chopped nuts (walnuts, almonds, whatever you enjoy)? Or you could mix in peanut butter to your oatmeal.
You could make yourself an omelette of whole eggs or a combination of whole eggs and egg whites, cooked in a tsp or two of olive oil, and stuffed with turkey breast, avocado, and a bit of cheese (full or reduced fat). That'd give you lots of protein, healthy fat, and good calories to keep you full.
There is no need to go both low fat and low carb, or even to go strictly either one, to control blood sugar. The Mayo Clinic Diabetes Diet (
http://www.mayoclinic.com/health/diabetes-diet/DA00027), which is designed to control blood sugar in diabetics, recommends both a moderate intake of high-fiber, whole grain carbs (up to 50% of calories) and a moderate amount of healthy fat (20-35% of calories).