Bri at Fat Lot of Good already had an excellent commentary on this somewhat surprising story (not surprising in it's information most of us fat activists already know, surprising in that a top obesity doctor finally fessed up to it).
To answer that question, Ernsberger took genetically obese and genetically thin rodents and made the thin ones fat by feeding them a high-sugar, high-fat diet. "They both had obesity related problems, but the one that has a poor diet is much less healthy — they have worse blood sugar, worse blood pressure and worse cholesterol.
"So all risk factors are worse off, even though they may not nearly be as heavy as the genetically obese." He says some people are naturally obese and other people are naturally thin but that they force their bodies to become obese by over-eating and under-exercising. "And that's probably the unhealthy obese."
Yes, yes, yes! So like in the "study" I talked about yesterday lumping all fat people and their variety of lifestyle habits is very misleading. Being fat alone is not the major risk factor. Correlation is not causation.
I know I have to be one of the genetically obese under his definitions. I exercise regularly, about an hour of lap swimming three times a week; I eat a much healthier than average diet, most days it's likely even on the low calorie side; and I have very good blood pressure and blood glucose but I'm still very fat. If I try to lose weight it wouldn't be for health reasons as I'm not sick. In fact I would likely be putting my body under risk again because of the stress of starving myself and the inevitable regain would in itself cause metabolic problems.