Earlier quoted context omitted.
Beat me to it. Before we were obese, we were already smokers, alcoholics, gambling addicts, sex fiends, violent thugs, opium lovers... if there is anything we can abuse, we will. Animals don't know when they're having too much of a good thing, evolutionary instincts are honed on getting as much as you can today because you could get none tomorrow.
And modern psychological research have shown the corporations just how to game those instincts for profits...
We have free refills in Canada and they're basically just abused by teenagers and poor people so three people can drink from one soda.