Our bodies crave proper nutrition, by which I mean vitamins, minerals, and other healthy essentials. When we do not get them from the over-processed foods and crops grown in mineral depleted soils, we often are still hungry no matter how much we eat. And so we eat and eat and eat and are still not satisfied.
Consider also the explosion of fast food restaurants, microwaved crap meals and the increase in consumption of carbonated soda drinks.
I know of people who have lost weight simply be eliminating soft drinks and doing nothing else. I once did it myself.