If you’re fat, blame your genes!
Actually, obesity is not a joke. It is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health. People are generally considered obese when their body mass index (BMI), a measurement obtained by dividing a person’s weight by the square of the person’s height, exceeds 30 kg/m².
Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.
Proved that excessive food energy intake and lack of physical activity play the main roles, there is also a genetic susceptibility and in the later years a theory is getting a foothold: the Thrifty gene hypothesis.
The recent rise in obesity and type 2 diabetes rates has reached high levels, due to more food availability and sedentary lifestyle, but this is not widespread through all people that eat a lot and are lazy. Why?
In 1962 geneticist James Neel proposed the thrifty gene hypothesis to partially explain the rise in Type 2 diabetes in the world and he suggested genes which predispose to diabetes (called ‘thrifty genes’) were historically advantageous, but they became detrimental in the modern world and by progress. Neel’s primary interest was in diabetes, but the idea was soon expanded to also encompass obesity.
Thrifty genes are genes which enable individuals to efficiently collect and process food to deposit fat during periods of food abundance. According to the hypothesis, the ‘thrifty’ genotype would have been advantageous for hunter-gatherer populations, especially child-bearing women, because it would allow them to fatten more quickly during times of abundance. Fatter individuals carrying the thrifty genes would thus better survive times of food scarcity. However, in modern societies with a constant abundance of food, this genotype efficiently prepares individuals for a famine that never comes. The result of this mismatch between the environment in which the brain evolved and the environment of today is a widespread chronic obesity and related health problems like diabetes.