I never watched nor counted calories, and my weight stayed pretty steady for most of my life ─ which I maintained by regular exercise and not going overboard on the sweet treats. Just over a year ago I started a meat-based diet (ketovore), strictly for general health, where I severely limit carbohydrate intake along with an increase in fat (!) which includes butter, bacon, eggs, and fatty red meats.
Without trying to lose an ounce ─ as I was content with my weight ─ I dropped just over 20 lbs in a couple months and have maintained that level this past year. I eat as much as I want, whenever I feel hungry, and balance it off with intermittent fasting (ie, all of my eating is limited to an 8-hr time period each day from about 10a-6p, with no eating over the remaining 16 hrs).
For me I find weight is directly controlled by carbs, and they were tough to give up as they are in some of the tastiest items of my old diet ─ pizza, cakes, pies, breads, pastries, donuts, pasta, cereal, potato chips, candy, etc. But for health reasons I also cut way back on sugars, so there's a lot of overlap there. Right now I'm at the trimmest weight I've been in decades, blood test results are excellent, and I feel the healthiest of my life.
Can't say I don't miss those delicious carbs...