This is part I of the my three part Master Series on Nature Wants Us to Be Fat.
Part I is on the existence of a biological switch to become fat, that it can be triggered by intake of added sugars such as table sugar (sucrose) and high fructose corn syrup, and that it activates a metabolic response characterized by hunger, thirst, foraging, a decrease in energy expenditure, the accumulation of fat, a rise in blood pressure, and the development of insulin resistance.