gotta feel sorry for them rats!  I've spent the last year delving deeper and deeper into the western diet and modifying mine to optimise my health. The main problem it seems is the processed food which contains high amounts of fat and sugar, further exacerbated by processed salt.  

cut out sugars and you're half way there it seems. once you cut out sugars your body will burn it's preferred fuel; fat.  as long as you are eating a high carb intake your body will never burn fat. it has to burn carbs first. once your body become a fat burning machine you lose weight fairly quickly. Similar to Atkins, it seems surprising that you can eat a full fat diet and be slim. Your blood tests should also show text book health after 6 months of a low carb, high fat diet. A high fat, high protein diet with (low carbs) is essential for proper maintenance of your organs. if you add in a lot of the right kind of veg, nuts, salad and oils you should see an improvement in every aspect of your health. eating a low fat diet with lots of carbs is not very healthy. I've mostly been eating a mediterranean diet. massed of olives, salad and meat. It's not as crave-worthy as a pizza but it works for optimal health