Consumer Reports magazine, in 1987 sponsored a laboratory test of all popular cereals, these included granolas, sugared, unsweetened, flaked, shredded and shaped; at the end of the test only Cheerios of all the cereals performed on par with an established full-nutrient lab rat diet used to assess similar rats in diverse studies.
Some of the rats on other cereals starved, or became weak, lethargic or failed to mature to the point of reproduction.
No milk or sweetener was added to the cereals as they were poured directly from the box to the bowl..
All rats had plentiful water available throughout the test.
I liked Oatios better. Used to get them in a fifteen pound bag from the coop