Sure, here's a USDA article referring to the "1984 Food Guide Pyramid" where it states cereals should be whole grain (see p38: https://www.ers.usda.gov/webdocs/publications/42215/5831_aib...)

As for whole grains vs fruit vs vegetables, here's a SR and MA of studies looking at different food groups and the RR of all cause mortality: https://www.sciencedirect.com/science/article/pii/S000291652...

Three servings of whole grains per day: 0.79 (21% reduction in ACM) Three servings of vegetables per day: 0.89 (11% reduction in ACM) Three servings of fruit per day: 0.90 (10% reduction in ACM)

So the evidence seems to support the suggestion that consumers should focus on whole grain consumption as a base for their diet.