* in rats Rats are pretty good models for humans, but they are a leaky abstraction like all models. Obviously no one is arguing junk food is good for you, but

* in rats Rats are pretty good models for humans, but they are a leaky abstraction like all models. Obviously no one is arguing junk food is good for you, but rats have rather different dietary and metabolic needs than humans. Both Homo sapiens and Rattus norvegicus are garbage disposals of the animal kingdom, but believe it or not humans are actually a little better equipped to handle extreme diets vs rats. Feeding lab rats ultra-high fat diets is pretty much guaranteed to result in obesity, insulin resistance, and all the problems that come with it, but Inuits and other groups have survived thousands of years with exactly such a diet for large parts of the year. Also, rats are wicked smart and even the "human" conditions for lab rats are likely insufficiently stimulating physically and mentally.