In general, the best advice that I have heard is to forget "exercise" but get off your ass and be active.
Eat whatever you want, in moderation, and limit the number of heavily processed foods that you indulge in.
Fats, have a high satiety value. Which means that if you include some fat in a meal, you will feel fuller than you would, had the same meal been fat free. Well out of proportion of the calorific value of the fats included