Let’s get this straight: bad diets and bad exercise can cause increased mortality. Bad diets and bad exercise habits are often (but not always) related to obesity. Therefore one can easily make a correlation between obesity and increased mortality. But that’s all it is, a CORRELATION. The CAUSE is still bad exercise habits and bad diets. A thin person who has bad exercise habits and a bad diet (and yet, remains thin) is at no less of a risk of increased mortality. An obese person who has a healthy diet and good exercise habits has a lower reisk than a thin person with a bad diet and bad exercise habits. So, insisting that fat/obesity = increased mortality is faulty (at best) logic. It is not the fat/obesity that is the cause of this. It is diet and lack of exercise. Not the obesity in and of itself. STOP CONFLATING CORRELATION FOR CAUSATION. It is incredibly dangerous!!! It ignores the dangers a thin person with bad diet and exercise habits face (as I pointed out with another example — of the thin, athletic guy who was having seizures caused by nearly fatally high cholesterol levels because doctors didn’t think to check that, after all, he was thin). It makes people assume that fat people are unhealthy — which is a false assumption.
Bean (ALAS! blog)