News flash–it's not so much what you eat but how much. In other words calories do count. There have been attempts among somediet "experts" to emphasize the mix of foods, ie proteins vs carbohydrates vs fats as determining ultimate weight. But this recent Wall Street Journal article seems to simplifyy matters. http://online.wsj.com/article/SB10001424052970203462304577138993430777580.html?mod=WSJ_hp_mostpop_read#printMode
In fact it is much more consistent with the science behind weight gain–namely calories ingested vs calories burned. Science has always documented the higher calorie count per gram of fat as opposed to protein and carbohydrates. And there is the added effect of carbohydrates raising blood sugar which in turn stimulates insulin secretion thereby contributing to fat accumulation.
But the article states that all forms of food groups when ingested in excess of bodily needs will ultimately be converted to fat and therefore weight gain.
So it may be valuable to balance the source of calories from among a variety of food sources, but ultimately calories still do count.