I've recently read "The Obesity Code", by Jason Fung and have applied and bought into much of Fung's theory of insulin resistance driving much of the world's obesity. The idea of a chemically manipulated set point and insulin resistance may not be mutually exclusive either. Pollution in our environment could also cause disruption in insulin and other hormones that regulate satiety.
I've shed 14 pounds since April by adhering to a low carb (50 or fewer grams daily) and avoiding any low- fat foods ( fat usually replaced by refined carbs) and I'm feeling great. Caveat, I'd gained nearly 20lbs. from Jan 8th to early March 2021, as I was prescribed a decent dose of the cortico-steroid Dexamethasone for several weeks. I'd had brain surgery to stereo-tactically ablate brain cancer cells. Dexamethasone, given to prevent brain swelling, disrupts the hormone insulin, My blood sugar levels became pre-diabetic, and I woke each morning with hunger that I'd never known before. I ate like crazy, craving refined carbohydrates. I now buy into the idea that in our world of food-abundance, regulating our insulin production and preventing insulin-resistance is pivotal to staying fit.