Too much - obesity, diabetes and CVD

There are different theories than can explain why obesity, diabetes, CVD (Cardiovascular Diseases) are epidemic diseases growing and spreading all around the world. To explain their persistence, Neel suggested that a “thrifty genotype”, which modified the regulation of insulin release and glucose storage may have provided a survival advantage for some of our hunter-gatherer predecessors [48]. 

This metabolic profile would have permitted these individuals to match cycles of feast and famine with proportionately large fluctuations in blood insulin levels, allowing them to efficiently store excess energy and better survive through periods of famine and food scarcity. However, now given modern Western society´s plentiful food supply, this genetic disposition has come to be detrimental to the descendants of these individuals. The hypothesis proposes that this thrifty genotype in the modern abundant food environment may be responsible for the elevated insulin levels and excessive energy stores in some type-II diabetic individuals, and has contributed to the insulin resistance and obesity that has come to characterize many of these patients [49].

The amount of fat in the human diet has probably varied considerably over time, with seasonal influences and geographic location [11]. Currently, Western diets are enriched in pro-atherogenic (accelerates the deposit of fat within the walls of the arteries) saturated fatty acids predominantly from domesticated animal fats and increasingly from palm oil in processed foods. At the same time there has been an increase in the intake of even more atherogenic trans-fatty acids generated in foods during processing procedures such as hydrogenation, which solidifies oils for the production of margarine and shortenings [50]. Both saturated and trans-fats have a direct link with elevated low-density lipoprotein (LDL)-cholesteol levels in humans [51], which predispose to CVD [11].

Considerable evidence suggests that many common diseases can be prevented by hunter-gatherer diets. Apparently, human nutritional metabolism in not perfectly tuned for recently introduced staple foods, such as cereals, dairy products, added salt, and refined fats and sugar [52].