The idea that the obesity epidemic today is the result of people being "weak minded" is ABSURD. If you look at the stats, you'll see that obesity rates took a big jump from the 70's to the 80's and have been growing dramatically since. Obviously, our genetics didn't change in that short time span, but do you guys honestly believe that a giant percentage of the population suddenly got lazy and weak willed that decade? Do you seriously think that every third human being today magically has far less will power today than people in the 60's and 70's? If anything, people make more of a conscious effort to diet & exercise today than ever before. And yet the number of obese people is astronomically higher than ever before. You have to be completely blind to assume this is the result of some collective failure in self control.
What is the real reason? I don't think we know for sure, but it probably stems from a number of factors. A major one is likely the MASSIVE changes that have happened to our food supply in the last 100 years. Store shelves are lined with far more hyper-processed "food products", the worst quality food is the cheapest, everything has added sugar, fat, salt, livestock is fed a diet they didn't evolve to eat, and even fresh fruits & veggies have less vitamin content now than in the past. I'm sure there are other factors as well, such as changes in family structure & behaviors, but the point is this: there are many EXTERNAL factors that are contributing to obesity.
In other words, it is much HARDER today to stay lean & fit than it ever has been in the past. It requires a STRONGER will and far more effort to avoid obesity. Think of how many people these days have to carefully watch what they eat and make a conscious effort to exercise. These were NOT things the vast majority of people worried about 50 years ago. They just didn't have to. This doesn't mean it's ok to take no personal responsibility for your health today, but the condescending & sneering attitude here that automatically treats obese people as "lazy" is incredibly counterproductive. I'd also add a side note that the "lazy" argument often has cause and effect backwards: becoming obese often leads to being lazy and not the other way around. Think about it.