Gorillas and diet at the Cleveland Metroparks Zoo. Both Gorillas have heart disease. I find it very interesting that as the sugar in their diet went down, behaviors not observed in the wild (but observed in captivity) went down. Let’s do a study on decreasing sugar in children’s diet, increasing vegetables, in a population of students that is high in behavior problems and observe the changes in behavior their. Oh wait, that’s been done a lot.