... In the event of global apocalypse, the relative popularity [of Keto diets] may increase, as most people who survive will be wealthier and more likely to have a diet fetish. ...
I foresee a very different scenario. In the event of a global apocalypse there will be gang wars fought over the remaining local resources and the rednecks who have all the guns will kill everyone else. They eat meat but also lots of carbs.
In a global apocalypse, there will be widespread famine and disease. Those who survive will do so eating anything that sustains life. Including carbs and fat. But once the carbs are gone and the population has collapsed, humans will be back in the stone age, but with the knowledge to restart agriculture pretty quickly, but they'll also start hunting for sustenance.
Finally, the obesity epidemic will be solved.
After a global collapse, some of the survivors will know how to grow food, but there will be no fuel for tractors. "Agriculture" will be more like subsistence gardening. Of course, most people have no idea how to grow food or hunt.
I agree that obesity will cease to be a problem because calories in any form will be scarce and hard to come by. I'm hoping that I die peacefully of old age before it comes to this.
One lesson from this virus is that the more people there are in the world, the greater is the threat from pandemic diseases. The sci-fi enthusiasts want us to build a system that could deflect an approaching asteroid, but it's probably a lot more likely that the thing that wipes us out is a germ. That, combined with a political system that nearly guarantees that we'll be ruled by megalomaniacal demagogs who know how to whip up public hysteria to get themselves elected, but once in office are incompetent to run a country.
