I think this idea of displacement works better and better still if a person has the tendency to eat unhealthy foods, like refined carbohydrates.
You said that wheat seemed to be bad for you. Could it be the form in which you were getting the wheat? Whole wheat is better for you than refined.
Similarly with rice. Refined or "polished" rice, white rice, has important nutrients removed. It's got mere fractions of the fat and protein and fiber of brown rice. It's too easy to digest, so it ends up getting stored more readily as fat.
And, of course, no weight loss effort stands a chance without exercise. At least daily walking.