humans basically crave 3 things, salt, fat and sugars, this is just the way it worked out through evolution, those are rarer flavors to find in nature and without processing and so we sought them out but werent ever able to obtain a great deal of foods which satisfied those cravings.. fast forward to today we are still programmed to crave and search out those things only now its available on every street corner we are literally surrounded by products which are salty, fatty and sugary. this fact coupled with an increasingly sedentary lifestyle is causing the obesity problem..