I think it's great to try to eliminate foods that you believe aren't healthy (in any quantity) from your diet, but if you replace those foods with a quantity of other foods that keep your caloric intake more or less the same, you're not going to lose weight.

> ... I ate very small portions for each meal.

That's what does it. Decreasing the calories you eat.

> I'm not sure why I can't change my habits such that I continue to eat those small portions (now that the fear is gone).

Because, like all of us, you're only human, and human psychology, plus how our stomachs and brains signal each other, is complex and sometimes makes it really hard for us to achieve our goals. It sucks, but that's how it is. This is why the semaglutide weight loss drugs are proving so effective: they short-circuit some of that and help you just not want to eat as much food.

If drugs aren't for you, try counting calories, and use an app to help with it and help keep you honest. I experimented with it back in 2017 or so, and it actually did cause me to be more mindful about how much I ate, and made me think twice if I'd already hit my calorie budget for the day but wanted more food. I was pleasantly surprised to find I actually did lose weight. I didn't stick with it (don't remember why), but it did work for me for a time.