Applying the 80/20 rule, metabolisms most certainly are not more complex than than a simple input/output equation for a vast majority of people. We have been a

Applying the 80/20 rule, metabolisms most certainly are not more complex than than a simple input/output equation for a vast majority of people. We have been around in this planet for thousands of years, a vast majority of which spent by a vast majority of people in a non-obese way. Evolution has tuned our bodies not to be overweight so long as we don't change the equation of calories in to calories expended. Our modern North American lifestyles have adjusted both sides of the equation, hence, obesity is an epidemic. Adjusting the equation back is a huge step forward, regardless of outliers. Look at the military. Diets aside, the simple reason there are no large obesity issues within the organization is that they purposefully modify the output side of the equation. Diets don't work because the modification to the input side is always only a temporary change. We eat too much and move too little. Duh. While the dynamics become more complex at the elite athlete level, and there is a segment of the population that could be considered outliers, if we all simply made the equation balance, we'd see a huge drop in obesity rates. It isn't rocket science.