Somewhat nit-picky, but I would push back against the simplicity of a few things you described. Overweight/obesity is influenced by numerous factors - exercise

Somewhat nit-picky, but I would push back against the simplicity of a few things you described. Overweight/obesity is influenced by numerous factors - exercise being one of them. In general, exercise has been shown to be a far less effective factor in controlling weight when compared to diet, but that's not to say exercise isn't important to your weight/health, because it is VERY important. I would say most of the world isn't obese because their food environment combined with biological/psychological/social factors is different than that of the US, which seems to be conducive to the development of obesity. I agree that habit forming is very difficult - and specifically that, given somebody doing no activity, starting them with walking/aerobics vs a relatively specific/strenuous exercise like pullups is a good idea. I think obesity is influenced by urban planning - in the context that obesity is influenced by many environmental factors. Like the US's obsession with car-sprawl at the expense of integrating activities like walking/cycling into one's daily life. You should read about some of Herman Pontzer's research: https://dupri.duke.edu/news-events/news/herman-pontzer-explains-where-our-calories-really-go-and-what-studying-humanitys https://dupri.duke.edu/news-events/news/herman-pontzer-expla... Specifically, that doing more physical activity doesn't mean you "burn more calories". You may also find his research on metabolism interesting: https://today.duke.edu/2021/08/metabolism-changes-age-just-not-when-you-might-think https://today.duke.edu/2021/08/metabolism-changes-age-just-n... (Age 20-60, it doesn't change much at all)