I've been tracking everything I eat in MyFitnessPal for over two years -- since about 5 months before my surgery. For me, this was key in changing my eating habits, both before and after surgery. I don't think it's counting calories, per se, that works, but the fact that it forces me to confront my food choices and get the most bang for the buck, calorie-wise. Constantly budgeting my calories has helped me to shift my food choices to low-calorie but satisfying foods. That's especially important now that I'm almost two years post-op and I can eat pretty decent portions (compared to the first several months post-op when I could only eat tiny quantities). If I weren't choosing low-calorie foods, I think I could easily get enough calories to start gaining the weight back.
A lot of people swear by "intuitive eating," and if that works for you, great, but I don't see it working for me. I think my intuition had to be pretty out of whack to get me to 341 pounds. I think it's possible that I've changed my eating habits enough at this point that I could stop tracking and be ok, but I don't want to put that to the test. I eat mostly the same things over and over, so if I stick to that, even without tracking, I would probably stay within the same calorie range.
I do have a hard time when traveling or eating at restaurants because it's difficult to guesstimate when someone else is preparing the food, but I very rarely eat at restaurants, so I try not to stress too much over the occasional meal that's not 100% accurate. I've also relaxed a little on weighing and measuring some things because I've gotten a good sense of portion sizes (e.g., half a small avocado is about 50 grams on average; 6 slices of thin-sliced turkey lunchmeat is about 75 grams), and some things are low enough in calories that it's not worth the trouble (e.g., I don't measure salad greens or cucumbers or tomatoes).
I like Dr. Weiner's approach of "a pound of cure" (which involves eating at least a pound of vegetables every day) because focusing on eating a lot of vegetables helps me to fill up on foods that are nutritious but low in calories. Every week, I meal prep daily veggie trays (carrots, celery, cucumbers, grape tomatoes, and peppers), and that's my main snack for the day. I also add cauliflower rice to a lot of meals to make them more filling without adding a lot of calories.