Causes of the Obesity Epidemic

A Complex Set of Factors

It is difficult, if not impossible, to pin down the cause of the obesity crises to just one or even a few factors. Obesity results when a person takes in more calories than expends on average each day. The difference between these 2 calorie flows does not need to be a large number, but only consistent over a long period of time. Since many items or factors go into each of these calories flows, we can consdier the imbalance to be the small difference between large numbers. Thus a some change in any one of the sources or uses of calories can cause the net energy balance to change.

"Why is this [the obesity crises] happening?

The rising epidemic reflects the profound changes in society and in behavioural patterns of communities over recent decades. While genes are important in determining a person's susceptibility to weight gain, energy balance is determined by calorie intake and physical activity. Thus societal changes and worldwide nutrition transition are driving the obesity epidemic. Economic growth, modernization, urbanization and globalization of food markets are just some of the forces thought to underlie the epidemic.

As incomes rise and populations become more urban, diets high in complex arbohydrates give way to more varied diets with a higher proportion of fats, saturated fats and sugars. At the same time, large shifts towards less physically demanding work have been observed worldwide. Moves towards less physical activity are also found in the increasing use of automated transport, technology in the home, and more passive leisure pursuits."
World Health Organization