I didn't know there was any fear of a "fat planet." I thought it was fear of a fat America. And yes, it's overblown and I'll tell you why. If the US economy continues on its current path most Americans will soon be too poor to afford fattening food. People were a whole lot skinnier during the great depression.
Yes... but during the Great Depression there was not the profusion of high-fat, high-sugar, inexpensive fast food available that is available today, nor was there the profusion of inexpensive, convenient, prepackaged, processed food with fat and sugar added to improve the taste and preserve the contents. Fresh food is, when looking solely at unit price, more expensive... until you start accounting for how much of the price is for the packaging and processing, and start to realize that the cost of fresh food - which is often more nutritious - is lower. Less convenient, which is, to be sure, an issue in this country - but less expensive (or, at least, not more expensive) and more nutritious.
As far as the article itself, for far too many years, "healthy" has been equated with a certain physical appearance. For men, that hasn't been
too bad, as the physique considered "healthy" for men involves the development of a certain level of musculature - possible for most men to attain. For women, however, the "ideal" - as seen in far too many runway models - is taller, more slender, and generally beyond the average women, unless she happens to be born with a particular bone structure.
Until the last century, when food supplies (in First World countries, at least) became more assured, and less dependent on local meteorological conditions, being overweight was uncommon, especially in the working class, because physical labor was necessary, for most, to survive - and thus the "common" person tended to be stocky rather than fat, due to the exercise encountered in the course of a day, and to eat quantities of food we would consider excessive, as they were necessary to maintain the energy output their daily activities required. Indeed, in the musical version of
Fiddler on the Roof, which is set (more or less) in 1916, Tevye sings in "If I were a Rich Man" that one of the indicators would be "my wife, my Goldie, looking like a rich man's wife, with a proper double chin".
As industrialization proceeded apace, and peoples' leisure time increased with the advent of machines to do labor that was previously performed by hand (anything from driving a car instead of horses to an automated washing machine instead of a wringer), it became (again) fashionable to appear to do no work - to have manicured nails, polished hair, beautiful (but impractical for manual labor) clothing, etc. - in short, it was fashionable to
not look like someone who did physical labor for a living. In previous times, such appearance was limited to the uppermost social class, but as there became a greater variety of jobs available that did not require manual labor, this opinion of "fashionable" spread, gradually, to the middle class as well. Those who could not obtain such jobs would still aspire to appear like those who were above them financially, and thus socially.
In mid-60s, with the introduction of Twiggy, the next step in women's fashion appeared,. in contrast to the previous, Marilyn Monroe-inspired look (a "perfect" 12, where today's runway models wear size 0)... it became fashionable not only to look like one did not work, but to look like one could not work - certainly, Twiggy did not appear to be physically robust (whether she was or not, I can't really say). When I was a teen, I recall the doctor at my annual physical adding 3" to my height so he could determine my height/weight ratio correctly, as the chart assumed that all females would be wearing 3" heels... and since I was wearing sneakers, he had to adjust for that.
This trend has intensified over the last several decades to the point where the "average" woman
cannot look like the "ideal" woman (that is, a runway model), unless she is blessed with a certain height, bone structure, and genetic predisposition to a certain build, and the determination to maintain it. This has nothing to do with health, and everything to do with fashion. I don't know that a "healthy" weight for adults has truly been determined - especially for women.
Certainly, there are certain medical conditions that are linked to obesity, there are certain disabilities that improve or resolve completely when weight loss occurs, and severe obesity (double or more the average weight) is a disability in itself - but I would be hesitant to go farther on the information available today, especially as frequently as the medical field changes its collective mind on what is "healthy" in relation to weight, nutrition, supplements, water, and medications.