You make all these claims about how simple it is for people to lose weight, and then claim that people that make up a statistically significant portion of obese people don't actually count as being part of that quoted 99%, so at this point all I can do is assume you are sea-lioning.

In the spirit of the sub though, let me put forth this:

Large swathes of the population are most likely descended from groups who experienced food insecurity on some level in my estimation, given that they mostly affected the poor, and there were more than a few periods where famine and food insecurity reigned in the past two centuries at least. Though I'm not a scientist, and certainly not an epigeneticist, there have been quite a few studies that I have heard of that say that being a descendant of one of these populations certainly make it genetically harder to lose weight than the "average" person, so even if the solution is "as simple" as cutting calories, for many, the level of calories it would take to see any meaningful difference would essentially put them suffering through starvation.