http://healthland.time.com/2013/01/02/being-overweight-is-linked-to-lower-risk-of-mortality/
http://www.express.co.uk/life-style/diets/455337/Fat-and-fit-Stay-physically-active-and-live-longer
There are articles and studies ‘proving’ health benefits of homosex and doing drugs.
‘Healthy fat’ is part of this narrative.
There was the whole lot of stupid things like that in human history, all backed by some kind of scientific researches.
Of course being fat is not by itself fatal, and being thin isn’t excluding possibility to develop serious medical conditions but it doesn’t make any tendencies.