Carbs
In Part 2 of this series, micro-nutrients were cited as a non-factor for weight gain. This is not the case with macro-nutrients (carbohydrates, fats, proteins, water). While fats, proteins and water are essential (without them you could not live), carbohydrates, on the other hand, don't appear to share this status. As Dr. Christian B. Allan and Dr. Wolfgang Lutz state in their book Life Without Bread: How a Low-Carbohydrate Diet Can Save Your Life:
"To our knowledge, there has never been an essential carbohydrate discovered. Every carbohydrate your body needs can be made from either protein or fat."
Wow - powerful words, indeed. This is not to say that carbohydrates do not add healthy value to our bodies (such as fiber); rather is puts their contributions into perspective. This makes looking at the above chart very disturbing as it shows we've been wolfing down carbs more and more for quite some time - a nutrient that we simply do not need in large quantities, much less ever increasing quantities.