What Causes Obesity?

Why are some people obese and others not?

There are multiple factors which can interact to lead to obesity.

Obesity is always due to the consumption of more calories than is needed by the body for energy. These extra calories are then converted by the body into fat which is the body's way of storing energy for a "rainy day". The "rainy day", however, never arrives and the fat/weight is not consumed. It may come on quickly if large amounts of food are eaten over a few weeks or slowly over many years if there is only a small excess in calories. In other words, a few grams a day when taken over a year equals a kilogram, and over twenty years is twenty kilograms.

There is a strong genetic tendency to obesity, and this is why obesity can be a family problem. Studies involving identical twins separated at birth have shown that they almost always end up being the same weight despite their different environment. If you have one parent who is obese you have a 50% chance of being likewise. If you have two parents who are obese you have an 80% risk.

This is not to say that our environment is not to blame. Food in the Western world is cheap, in abundance, and is marketed very aggressively. We therefore have an abundance of calories.

Automation of our environment has also lead us to be more sedentary. With this comes the need for less energy to function. Instead of taking the stairs, we take a lift, instead of walking, we take the car or bus. Somewhere along the line our energy requirements become less than what we consume and consequently put on weight.