I've seen articles on different sites which describe experiment on rats. One group of rats was fed corn flakes, another one - cardboard box of those flakes. The corn flakes group died first.
E.g. Something You've Never Been Told about Breakfast Cereals on/from 'Wellness Support Network'
"Another unpublished experiment was carried out in the 1960s. Researchers at Ann Arbor University were given 18 laboratory rats. They were divided into three groups: one group received corn flakes and water; a second group was given the cardboard box that the corn flakes came in and water; the control group received rat chow and water."
"The rats in the control group remained in good health throughout the experiment. The rats eating the box became lethargic and eventually died of malnutrition. But the rats receiving the corn flakes and water died before the rats that were eating the box! (The last corn flake rat died the day the first box rat died.)"