I don’t think I oversold it at all, it’s just a calorie balancer, it’s not going to do anything else, and it won’t fix a bad diet…
But it does work; it’s just a standard biological mechanism. If you shiver, you burn a ton of energy to do so, it comes from fat. This is true in any species with the shiver capacity, that’s what it’s for.
Bigger people need more shiver time and lower temps, which makes it harder to see the result, but it still works.