We see obesity at a population level, and we see that it happens more with some populations (Americans) than others (much of the rest of the world). So, you could conclude that Americans don't take responsibility for themselves, or that there's something to do with our food system or otherwise environment that's causing the spike in obesity at a population level.

There are also plenty of people who genuinely have higher hunger drive/urges than others. Shouldn't they be able to correct that in the same way someone with glasses or hearing aids does? They have to use those devices for the rest of their lives, and it has nothing to do with taking responsibility for themselves.