Body battle for obese people

Prof Proietto said obesity was often attributed to people eating too many high-calorie foods and not exercising enough.

But he noted not everyone who indulges in that type of behaviour becomes obese.

He said this was largely because the body acts to prevent obesity by increasing the levels of a protein hormone, leptim, as fat accumulates.

But when that process failed, people were likely to become obese.

Prof Proietto said such cases were rare and more people were likely to become obese because of genetic changes caused by environmental factors, either while a baby was still in the womb or in their early years.