One of the most important videos I've seen recently about what causes obesity is called "The Food Revolution AHS 2011"

I do agree with the first question at the end though. We don't know if the obesity epidemic is due to refined and other high-GI sugars or to any sugars (including low-GI that don't raise your insulin as much). I think that, it is possible that one doesn't need to go to the extreme of banning natural healthy foods such as fruit from our diet. Maybe just avoid eating too much of the high-GI ones (not many by the looks of it) Fruits have lots of great things such as anti-oxidants that we need to be healthier, fight cancers etc. But I've certainly noticed, upon banning sweets from my diet, that it was suddenly much easier to eat less, due to less sugar crashes and consequent hunger, and it was also much easier to eat healthier since healthy food started tasting much better. Keep in mind that, even if saturated fats aren't as bad as they were once thought, trans fats are apparently still considered dangerous.

I'm a guy trying to balance muscle gain and visceral fat loss, since my arms and legs are already ok. I'm trying to adopt a complete diet (ignoring no important food groups. Only high-GI carbs) consisting mostly of natural healthy foods. I'm focusing on making slow, sustainable and permanent changes to my diet since I believe that no temporary fixes work can work on a life-time goal. So far, I've managed to trick myself into slowly introducing vegetables and fruit in my diet. After this was achieved, I was able to slowly reduce consumption of artificial foods/ sweets/ junk food, all the while I've also been trying to loose weight and gain muscle. Right now, I'm at a point where I'm almost junk-food free and eating a reasonable amount of fruits, vegetables and fish in my diet. My next objective is starting to introduce more types of vegetables.