Why should the government be any different than their constituency?

How many people have you talked to who "can't live without bread" or "crave pasta every night"?

How strange did you think the Atkins diet was when you first contemplated it?

Sure, there are lobbies, and don't get be started on government subsidized Big Sugar. But at the same time they are mostly people like you meet every day. And how many of them can properly interpret conflicting scientific studies?

As for the scientists, if you have staked your academic reputation on low fat, it's not just closed mindedness that will make you not believe. It's serious denial.