It sounds like most of the interventions that you have been using are dietary, and that they are effective when she complies. You might try using an analogy that different people require different fuel to perform at their best, just as different vehicles require different fuels. You can't use the same fuel in a garbage truck that you use in a race car, but that doesn't mean that there is anything wrong with either of them, just that they won't perform at their best when they have the wrong fuel. She happens to have a brain that runs its best on racing fuel.
