Fat Not Good for Survival

Debunking the myth that fat protects from cold and starvation.

The notion that fat is better for survival as it protects from cold and starvation is a myth.

In theory, and without context, fat would indeed be seen as an insulator, and thus, beneficial to survive in the cold. However, human biology and nature are more complex. From a short term practical perspective, fat may indeed shield internal organs from cold exposure a bit longer, but this is greatly offset by various factors, including residual cold, as well as biological functions associated with obesity. When exposed to severe, moderate, or even mild hypothermia, fat is directly linked to longer recovery periods. In other words, once cold, it will take much longer, and inherently more energy, for an obese individual to recover. Fat is also associated with many health ailments, including lack of cardiovascular fitness, high blood pressure as well as a less evenly distributed blood flow in the body, all of which lower an individual’s resilience to cold. From a long term survival perspective, fat is also associated with cancer, heart disease and diabetes, which often deadly outcome would offset any alleged benefit of fat for cold weather survival.

Similarly, fat could be viewed as providing a source of energy for the body, and thus, be beneficial to protect an individual against starvation. Again, this is not that simple, and the concept would only be applicable in a modern society environment unrelated to evolutionary fitness, where starvation is not a risk anyway. Looking at passive survival, as in a sedentary individuals not involved in any physical activity, body fat will indeed delay death from starvation, and thus, increase short term survival. However, fat will not increase long term survival for a sedentary individual, and will not increase either short term or long term survival for an active individual. The reason is that fat affects an individual fitness and physical performance, and thus, his ability to source food. A fat individual will have much greater difficulty hunting and gathering food than a fit individual with lean body mass. Moreover, when it comes to using body fat as fuel, the human body is typically highly inefficient (unless specifically trained for it with proper diet, in which case there is no obesity consideration), and will tend to burn muscles first, further decreasing an obese’s individual fitness and ability to source food.

Whether from a short term, long term, or evolutionary perspective, fat is not good for survival, even when it comes to cold weather and starvation. One of the fundamental traits of survival is fitness, and everything that comes with it.