If I eat enough to sustain my obese body, I'm not hungry anymore. If I try to eat less, I'm hungry. I successfully lost 10kg, and first 5kg was even easy. I thought at start "ehh, that hunger is only a feeling, I can continue like that", but I couldn't and I'm back where I started. Just eating less may work for some people, but not everyone.

There are at least 3 hormonal ways, but such blood sampling is prohibitively expensive for now.

Of course it'd be better I'd you could just read it off neurons, too hard though.