I read a very interesting article today by Mark Sisson, the author of the bestselling health book The Primal Blueprint, that further supports the argument that the human body, by design, craves and depends upon a diet consisting of healthy saturated fats, not sugar (glucose; high carb diets), in order to run at its most efficient level.
The article, What does it mean to be fat adaptive, points out the differences between those who are sugar burners (sugar adaptive) and those who are fat burners (fat adaptive).
Those who are more sugar adaptive, which is probably the majority of people living in today's industrialized overly processed food era, have their bodies trained to seek sugar (carbs) as the primary fuel source. This is unnatural in that sugar compared to fat is not stored within the body at the same levels, ~0.69% of body weight at any given time compared to ~12% of body weight respectively. Since sugar is burned relatively quickly with more or less no reserves, the body runs out of fuel quickly requiring another hit of sugar (carbs), and because the body is "sugar adaptive" it becomes very inefficient (nearly incapable) of utilizing fat reserves resulting in increased fat storage. That in combination with the consistent spikes in insulin levels caused by high carb diets, diseases such as diabetes and those related to obesity become inevitable.
In contrast, those who are fat adaptive have bodies that utilize the body's natural fuel source (fat reserves) in an efficient and effective manner. This is a result of a diet that is higher in animal protein and saturated fat (animal fat, coconut, etc.) and low in glucose (carbs- especially grains, processed and refined sugars, processed foods).
I can honestly say from my own experience, I have seen and felt the transition in my body from "sugar burner" to "fat adaptive". Not so long ago when my diet consisted of high amounts of whole grains as a substantial fuel source (grains for breakfast, grains with lunch and dinner) I was hungry more often with irritability on an empty stomach, while experiencing almost diabetic symptoms (lightheadedness) from the obvious insulin spikes and glucose highs and lows. In contrast my current diet, high in protein and saturated fat (animal fat, egg yolks, coconut) with minimal grain intake, I have noticed more energy, an ability to go longer between meals without empty stomach irritability (within reason), and no more lightheadedness from insulin spiking.