Humans are designed to limit energy expenditure. Its hard wired in us from our hunter-gatherer days. That's not the root cause but it is a trait we all share. A

Humans are designed to limit energy expenditure. Its hard wired in us from our hunter-gatherer days. That's not the root cause but it is a trait we all share. Add to that a poor diet, one that makes you feel sluggish and makes you crave more food and drink. Throw in economies of scale to make the food super cheap and accessible. Pack people inside, throw a TV in front of them or any sort of thing that will give them an environment of relaxation and you've got yourself the makings of an obesity problem. The truth is, humans are lazy and will, by in large, only do work that they have to do.