According to Men's health, we should add no more than 10 grams of fiber per day in the beginning. They also suggest that you add them at night so you are not awake while your body is digesting more fiber than it's accustomed to.
I eat Kashi cereal. They make one that has 9 grams of fiber, 9 grams of protein, and 500 milligrams of Omega 3's in a one-cup serving. It's made with flaxseed oil so it's not low-calorie but the fat in it is good fat. It also has some potassium and other goodies your body wants but doesn't get enough of...