In the May 23rd Scientific American podcast on eating disorders in adult women, the scientist/author explained how people's metabolisms slow down when they diet. So when they fall off the diet, they gain more weight than if they had never started. Also, diets create cravings for the things you are forbidden to eat. She said all diets are ineffective and sometimes even cause weight gain EXCEPT Weight Watchers, because WW is a lifestyle change.
Re the preservatives and additives and whatnot. Is there evidence that these things are bad for us? Creepy, sure. But we are eating more of them and living longer than ever before. I haven't heard of anyone getting sick from them, except for ones that are already banned.
Edit: After some googling I found that they may increase
hyperactivity in children.
I'm not sure about the carbon footprint argument, either. How much carbon is spent on those bananas
per bunch? I looked for some data on this one, but couldn't find anything convincing.
But if the farmer's market stuff tastes better then go for it.