It's 4 inputs, actually. 1) The culture (active, passive). Example: Germany, where people bike a lot more since gas costs so much; and ironically, their shitty

It's 4 inputs, actually. 1) The culture (active, passive). Example: Germany, where people bike a lot more since gas costs so much; and ironically, their shitty Internet and cell service negatively impacts the phenomenon of everyone being glued to a screen. I think they're actually proud of it, at this point? Anyway, they're WAY fitter (despite, or perhaps partly because of, eating meats for breakfast instead of cereals!) 2) The food environment (preservatives, fructose, hidden carbs, bad artificial sweeteners, salts in everything, big serving portions, or more all-natural stuff) 3) Genes- There are literally over 500 discovered that affect your equilibrium weight. 251 genetic markers have been linked to sport-related traits (though only about half have been replicated in multiple studies). 13 genes have been identified so far that affect how the body responds to different types of exercise, including cardiovascular fitness and muscular strength. 4) And finally, there is willpower/discipline. Which is a finite resource, by the way, that gets resupplied by sleep and downtime, and which often needs to be drawn on for other things (like work and childrearing). Think of it as a dial. In the middle, you stay the same weight. Tilt it slightly to the right (which is all too easy to do), and you are on a weight-gain schedule. Tilt it slightly to the left, and you will lose over time. If you're working against (1), (2), and (3), then (4) becomes MUCH harder to do.