I do like Penn and Teller and their show, but I would like to see more statistics as to how around 20-40 people rated that food, not just half a dozen, and to see all of the results. There's no way we can tell how many people they did this test with. There are a lot of idiots influenced heavily based on what is popular or what a popular idea is.
There is a difference in the taste of water based on if it's tap and where the tap water is (the tap water in NY where they filmed is actually quite good), if it's been filtered with a brita, RO filtered, bottled with minerals added, etc. All that episode showed was how effective marketing is and that when people believe water was bottled from the Swiss Alps, it tastes good, because they have been told it tastes good.
This episode showed that many people have bought into the idea of all fast food being disgusting, stale, and unhealthy. Whereas sit down restaurants with healthy buzzwords in their name have great food that's very healthy for you. Those people not being able to tell shows that conventional wisdom and product marketing have a huge influence on their opinions.
It is bullshit to try to ban fast food and I'm not really sure who is seriously trying to do that other than a couple of towns full of pretentious idiots. It is good that restaurants now provide the nutrition facts at the actual table. That kind of regulation is good as it provides at least a quick way to get an idea of the healthiness of food before you order. I wish that had been their point instead of "don't ban fast food." Some new ideas of regulation to encourage healthy eating can be good, but considering how libertarian Penn is I doubt he'd be ok with it.