A few things I’ve learned over the course of a long life: if you want to program your body to crave healthy foods, go out into the wilderness for a long (30+ miles) serious hike (the sort where your muscles are perpetually aching and you are sucking in air) and take only healthy provisions with you. As your blood sugar drops and you consume these life-giving small mouthfuls of sustenance, your brain begins to associate them with satisfaction. Thereafter McSlop, ice-cream, etc. have far less appeal. Also, when you push yourself daily with exercise (running, not jogging; serious weights, not hotel-style stuff) your body automatically adjusts and wants real food, not candy and other forms of empty calories.
In our indolent everything-at-our-fingertips modern world, we’ve become so disconnected from true physical needs that we’re largely unable to self-regulate. Re-imposing more exigent conditions can very rapidly set things right.