I think that article is 100% misleading. The rats became addicted to highly processed foods full of fat AND sugar and 100% completely devoid of fiber, vitamins and minerals.

If you can show me how rats got fat eating only say pemmican or avocados, then you might convince me that the fat was the culprit.

As most everyone here has mentioned, it's the highly processed foods that we can't stop eating. And there is a reason for that - they've been created for just that purpose! McDonalds or Coca Cola or Kelloggs or Sara Lee WANT you to get addicted to their food. They remove the healthy stuff to make it more shelf stable and lo and behold - now humans can eat more of it and even better...they start to crave it! Wow - jackpot! Lets keep this up...what else can we process the crap out of in order to sell more and more and more???

It's disgusting. Admittedly, I'm a victim every time I respond to a desire for Cadbury's Mini Eggs (which are the work of the devil, I swear!) Me and those rats...we are both doomed.