Diabetes, coronary artery disease, hypertension, obesity are the main “underlying medical conditions” that increase risk of death from Covid19. Does this sound familiar? All are features of metabolic syndrome. And what is the overarching pathophysiology of metabolic syndrome? Hyperinsulinemia. Hypertension, one of the strong predictors of a bad outcome with Covid19 is not, in an of itself, necessarily associated with impaired immunity. Most cases of hypertension are associated with metabolic syndrome and hyperinsulinemia. It is not universally agreed, but a, if not the, primary mechanism for the association of hyperinsulinemia and hypertension is the upregulation of the renin, angiotensin, aldosterone, RAAS, system. One mechanism whereby insulin upregulates the RAAS system is by upregulating ACE receptors. See links to articles below. SARS-CoV-2 virus enters cells by attaching to the ACE receptor in lungs. So it should follow that the more active ACE receptors an individual has, the more opportunity the SARS-CoV-2 virus has to penetrate lung tissue leading to worse disease and mortality. According to a review of NHANES data, 88% of US population is metabolically unhealthy. If you want to improve your chances of surviving Covid19, you need to reverse your metabolic syndrome with a low carb, ketogenic diet.