I think it's related to diet, a deficiency in Vitamin D probably indicates a certain type of diet that leads to obesity. I wonder if metabolic syndrome and vita

I think it's related to diet, a deficiency in Vitamin D probably indicates a certain type of diet that leads to obesity. I wonder if metabolic syndrome and vitamin D deficiency are also comorbid. You need fat to absorb vitamin D and perhaps this fat has additional benefits (satiety, less feeding periods, the integral of insulin over time is smaller). Ketosis probably has some role to play, I should check if they're controlling for this factor. Until they can control for the entire diet it's hard to really tell based purely on vitamin D, the metabolic processes can be so complicated in a human. Disclaimer: mindless speculation above--I'm no expert, just a mathematician.