I used to be able to eat tons of total crap food without gaining a single pound, so also thought that all of those overweight people were really sneaking a pint of ice cream or something every night. Over the years, my eyes have been opened to the difficulties some people experience regarding their weight.
And with all due respect, asking people to run marathons or work out for 2+ hours/day is totally unrealistic. It’s this sort of mentality that causes overweight people to give up completely.
One more thing to keep in mind is that being underweight or normal weight does NOT mean that a person is fit or healthy. I’ve known quite a few overweight people who could easily outperform most skinny/normal weight people in almost any physically demanding task.
