Thrifty Gene Theory

Heart disease, type-2 diabetes and cancer are all diseases linked to obesity. Heart disease may be linked to obesity because an obese person has more body mass; therefore they have more blood, and a larger area that the blood needs to circulate through. This puts pressure on the heart to pump harder, and it strains the heart, leading to heart disease. Type-2 diabetes may be linked to obesity because often obese people consume large amounts of sugar. The body then tries to balance the blood sugar levels by overproducing insulin. Since the body is trying to produce so much insulin, it develops a resistance to insulin, or it cannot produce the right amount of insulin to correct the blood sugar levels. Cancer may be linked to obesity because an obese person would have more body mass, so they would have more cells in their body, and a higher chance of mutation among those cells. Cancer also may be
As it is mentioned in the article, babies with the thrifty gene may enjoy eating sugar because in the past their ancestors may have needed to start eating sugar and fats right away for survival. Since there is no way to explain to an infant that they need to eat whatever food is provided for survival, it may have only been the babies that instinctively enjoyed fat and sugar who survived to adulthood.

Allergies to peanuts and gluten may be becoming more common because in the past, most people with allergies would not have survived, because their condition could not be diagnosed. Those who did survive may have looked malnourished, so they would have been less likely to reproduce. However nowadays people can easily be diagnosed as allergic, and can be kept away from the cause of their allergy, without sacrificing their nutrition. Since they can then live to a reproductive age, the trait would get passed onto their offspring, and would be come more prevalent in the