Glucagon-like peptide-1 agonism - GLP-1, common in obesity medicines - is not essential to weight management, according to preclinical research led by Richard DiMarchi and Matthias Tschöp, with funding from their startup company Bluewater Biosciences.
If you know several people who met the medical definition of obese and have perminantly left that category then you know several outliers, which is entirely possible.
But that is just not representative. Over 99% of obese people do not lose weight. Those few outliers are heavily visible and celebrated so it feels like there must be more.