Nonsense. Where did you hear that?
Lot's of places, but not from Big Government and Big Agriculture.
Here are a few. Grains are relatively new in the human diet. I believe grains scar the arteries, and then colesterol builds up to 'heal' the scaring, and causes blockages. And heart disease. Lot's of other problems, as this sample of articles point out. But do your own research. I dropped 45 lbs, and shrunk my belly from 36 to 32 inched by cutting out sugar and grains.
http://www.mercola.com/article/carbohydrates/lower_your_grains.htm
http://www.eat-real-food-paleodietitian.com/Paleo-diet-reasons-to-avoid-grains.html
http://authoritynutrition.com/6-ways-wheat-can-destroy-your-health/
http://paleoleap.com/what-is-wrong-with-grains/
http://wellnessmama.com/575/how-grains-are-killing-you-slowly/