The second rat, which has been fed the average American diet—

This is very concerning.

Having been placed in a vat of water, a perfectly healthy rat was able to swim to safety every time.

The second rat, which has been fed the average American diet—complete with all the fats and sugars Americans regularly consume—doesn't know where to go, exhibiting symptoms typical of a human with Alzheimer's disease.

"His brain has been damaged."