When deciding what to eat, remember that it's not a choice between - "I will always choose nutritious whole foods" or "I will always choose cookies," like you need to decide which is better and accept the consequences of that choice forever. You can do either or both as it suits you. I do. It's not like I'm a cookie person now. I may eat two or three apples in a day, because I do really like them. It's when I'd love a cookie or a candy bar but tell myself I should have an apple that things get weird, especially if I then put four tablespoons of peanut butter on the apple. :-)
Instead of trying to think what's the best choice and backing it up with things you've read (working it all out in your mind), it's easier to eat something new or try something new and notice how it feels. Then it's not theory. You're basing your choices on your own experience.
Sometimes it can be a bit of a mental leap to choose what you actually want versus the low-cal, high-volume option you think you "should" have. I had to experience it for myself instead of trying to think it through. How does a grilled cheese sandwich satisfy versus veggies and quinoa? You can guess, or google it, or tell yourself made-up stories, or you can eat the grilled cheese and know exactly how it feels. Having tried that one for myself, grilled cheese is super satisfying. Anything with quinoa, not so much.
About the processed food and apple versus cookie, I think that was a really big breakthrough for me, when I realized that eating a full sized candy bar was fewer calories, just as satisfying, and definitely more fun than the peanut butter apple and dark chocolate combo I'd been calling dessert. I'm reminded of when Sohee Lee ate a full size Snickers bar every day in her prep for a figure competition, which she won. That really shakes up the notion of what's necessary or off limits for leanness. Another big aha came when I realized that on many menus, a burger and fries is fewer calories than the loaded salads I'd been ordering because there was lettuce. If that's the case, then what was going on at home when I was eating the enormous taco salads with avocado and cheese while my skinny husband had 3 tacos? He was probably eating less than I was, consistently, happily, obliviously. No wonder I was struggling with weight and he wasn't. I was forcing myself to eat substantial portions of a bunch of stuff I didn't especially want. I'd have been better off having the candy bar, or the burger, or the tacos than my restrictive workarounds. I tested this theory and was amazed that I started losing weight. I was also amazed at how much more I enjoyed my food, and how easy it was to stop eating.