Don't think that there is anything really new here.
I think the ongoing confusion results when people ask for simple answers to complex problems and the health community tries to give them. The vast majority of people do NOT scrutinize calories or quantities of foods consumed. Therefore they are only left with scrutinizing WHAT they eat even though this is only half of the equation.
The human body has evolved systems to utilize both saturated fat as well as carbohydrate. What it has not evolved to utilize (well) are trans-fats (a synthetic trans-fat) and processed, high GI carbs.
The way that I look at it is both quantity and quality of food is important and the two are proportional. Meaning the more you eat a certain food, the higher quality it should be. If you are on a low carb diet then the odd bit of candy is not going to be significantly harmful, however if you are on a high carb diet then the bulk of it should be whole fruits and low-moderate GI legumes and grains. The same argument can be made for consumption of fats. This is the logic that leads to the common balanced diet recommendation.