@jholcomb - I think you've hit the nail on the head. I always tried to diet for weight loss doing the things you mention, like drinking diet soda. Now that controlling my PCOS is my diet goal, I've made much healthier changes.
It's hard because it takes a lot more effort, but it's worth it. I tried changing things gradually. I dropped my morning muffin and substituted a hard-boiled egg with a smidge of mustard, for instance. Instead of trying to eat a salad as my lunch, which left me famished so that I would then snack all afternoon, I begin lunch with a small salad (it does get you started filling up) and then eating something rich in protein and veggies, like a tuna salad that's way low on mayonaise and way high on celery and red peppers.