OK, so Ratland has a lot more healthy options than it used to, but you do have to seek them out among the usual stuff.
This topic has come up before, so take a look at a previous thread
HERE
Along with that, I have a couple suggestions:
1) fill up on fruit and protein (such as the eggs) at the complimentary breakfast - they will last you longer than the cereal/bagel/refined carbs and you won't get hungry so quickly afterward.
2) Take healthy snacks and water with you into the park. Maybe snag a banana from the breakfast spread
and eat/drink them at regular intervals to avoid the ravenous hunger that results from dehydration and lots of walking in the sun.
3) Be aware of your food options in the park.
This article discusses customizing the food (dressing on the side, etc) splitting portions with your companions, or ordering a kid's size to get the taste without the oversized portion.
This one does too.
Finally, I would recommend treating yourself to something you really crave. You are on vacation, after all. So, be aware of your calories, keep hydrated and make smart choices, and you should be OK splitting a funnel cake with your sweetie or having a nice dinner in DT Disney. Moderation, in all things!
EDIT: Found another great resource!
This blog post details a lot of the places inside DLand and California Adventure and what are good options on the menus etc.