Fizzy water. When you feel like a snack, drink some carbonated water. I found a lot of time I wanted water and flavor more than the food.

And high fiber/bran stuff fills you up. Get stuff made of whole grains like popcorn, whole wheat (or real corn) tortillas, fruits with peels on, and the like.

Blueberries freeze really well, spread em on a baking sheet so they stay separate before you bag them. Muffins are pretty easy to bake at home and with a little practice you can make a whole wheat muffin with sunflower seeds fucking tasty.

The pain in the ass is that healthy ingredients go bad much faster. Whole wheat flour goes stale in a hurry compared to AP flour.

One thing that worked for me was fasting. It is far easier for me to skip a meal than to eat in moderation. I figure I want to eat a 2000 calorie meal every time i sit down, maybe that's a sign I should only do it once a day, very much ymmv on that one, but I lost 50# in a year just ... eating until I was full, but only once a day.

As a nice side bonus, your bathroom schedule also becomes very predictable, which is handy for scheduling,