FashIntern, when I moved to Australia for a semester in college I, without particularly trying, lost about 20 pounds. Just because I was walking everywhere (and doing so was pleasant and not dangerous), eating smaller portions and all those little things that aren't much on one day but add up over time. For sure, most of the US is set up so that the default is to eat too much and move too little.
I've lost weight several times and eventually gained most of it back, but overall my health habits are improved from when I was younger. One of the factors for me is the antidepressants I take, some of which can make it harder to lose weight and easier to gain, but personally I'd rather be overweight and a functional person rather than skinny and suicidally depressed.
I think the fat positivity movement has a lot to recommend it. But I also think Jason Fung, Gary Taubes, etc. and the intermittent fasting people have a lot of scientific evidence on their side. I've never been able to stick to a really low carb diet myself, a) because starchy foods are so much more logistically convenient when you're busy or low energy and b) because becoming 'fat adapted' seems to be really challenging for me. If someone could just lock me in a room with only lean proteins and vegetables for 3 months, I'd get used to it, but access to sugar, unhealthy fats, junk food, etc., is so easy (unlike most of human history), and I'm definitely an emotional eater.