The obesity epidemic, as the author describes it, isn't a good thing, and for us to have BMI tendencies similar to those of late 19th century Americans would probably be better (excepting of course their other major health problems from that time) but in relative terms, I'd consider today's obesity problems in most of the population much better than the near starvation that most of humanity lived in during the vast majority of history, even up to the early 20th century.
For all but our most very recent ancestors, periods of chronic hunger was just a missed crop or bad harvesting season away and mass starvation was only slightly more distant. Famines were common in most of the world and often killed many millions per year, almost every year during millennia, of all ages, including children and infants. Obesity-caused deaths are still deaths but at least they tend far more towards killing later in life and are much more in the hands of any given individual to avoid, as opposed to starving because your whole region no longer has enough food to keep you living regardless of your dietary choices.
Generations of people prior to all but the last century or so of history would be amazed, and possibly even envious at how abuntantly and cheaply most of the population can feed itself today, even to the point of chronic obesity.