The epidemiology and aetiology of obesity: a global challenge.

Positive energy imbalance Energy imbalance leads to obesity. A majority of the US population is overweight, a third obese and nearly 5% morbidly obese. In the developing world, this problem continues to evolve in an rapid manner, creating challenges for already burdened health systems. In many instances, the environment contributes to the problem. Factors ranging from the availability of calorie-dense foods, decreased time spent in physical activities, technologically assisted household chores to time spent watching television, all have some contribution to the problem. Much more needs to be done to control this obesity epidemic, both from a public health as well as a communal-expense perspective. Forced misuse of economic resources and wasted potential lives should drive a better coordinated effort to control what could possibly be the biggest health challenge of the 21st century.