Analia Pecollo celebrates losing 11 kilograms during the Argentine TV show Cuestion de Peso (A matter of weight) in Buenos Aires. The show, similar to the U.S. TV show The Biggest Loser, has high viewership in a country where, an official report says, half the population is overweight and 12 percent is obese.

Obesity is defined as excessive fat accumulation that presents a risk to health. It is a major risk factor for diabetes, heart disease and cancer. Once a problem only in high-income countries, obesity is now rising in low- and middle-income countries. (© AP Images)