Sydney, Jan 5 (IANS): With nearly 76 per cent of the world's population becoming 'overfat', it has become the new pandemic that has quietly overtaken the world, a study has showed.

'Overfat' has been defined as a condition of having sufficient excess body fat to impair health.

"This is a global concern because of its strong association with rising chronic disease and climbing healthcare costs, affecting people of all ages and incomes," said lead author Philip Maffetone, CEO of MAFF Fitness in Australia.

In addition to those who are overweight and obese, others falling into the overfat category include normal-weight people, the researchers said.

"The overfat category includes normal-weight people with increased risk factors for chronic disease, such as high abdominal fat and those with characteristics of a condition called normal-weight metabolic obesity," Maffetone added.

"The overfat pandemic has not spared those who exercise or even compete in sports," he said.

While the obesity epidemic has grown considerably over the last three to four decades, the study casts light on the much higher numbers of people who may have unhealthy levels of body fat.

It also indicates that 9-10 per cent of the world population may be underfat.

"While we think of the condition of underfat as being due to starvation, those worldwide numbers are dropping rapidly. However, an ageing population, an increase in chronic disease and a rising number of excessive exercisers or those with anorexia athletica, are adding to the number of non-starving underfat individuals," Maffetone explained.

This leaves as little as 14 per cent of the world's population with normal body-fat percentage, showed the study, published in the journal Frontiers in Public Health.