Comment by valzam

I do think the point is also partly that what most people consider 'a good amount of exercise' isn't really very strenuous. Doing a bit of cardio and weights at the gym 3x a week isn't enough to offset a bad diet. If you run 10k every day, that's a very different ballgame because you meaningfully burn more calories than a regular diet gives you.

It's also incredibly easy, at least in America, to consume way too many calories. To meaningfully lose weight you have to drastically change your diet or drastically up your movement.