so much to learn...
Fat has nothing to do w/ it. Well, ok, maybe saturated fat. You should just make sure that the macronutrients you take in are from good sources. Fat is perfectly OK to eat, and is in fact a must, but it should come from good sources like walnuts, almonds, flax seed oil (uugghh), stuff like that. Carbs should come from LOW GI stuff like sweet potato as opposed to regular potato, whole wheat bread/pasta as opposted to regular if you must. Protein should come from boneless skinless chicken breasts, tuna, lean steak, protein powders, etc.
Do a search for diff types of diets. 40/30/30, 33/33/33 (isocaloric), ketogenic (CKD), low carb, and a bunch of others.
Hope that helps out some.