Obesity in children is a problem that affects all races and social classes in the world. Its exact causes are still under discussion, nutritional causes of lack of physical exercise, and genetic causes have been proposed. Recent research says that childhood obesity is possibly caused by a lack of muscular development problems of obesity in children are produced by less physical activity or a low metabolic rate, today there are some methods that seek to give solution to this dispute, to a theme of difficult solution. Learn more at: Steven Holl. Children with obesity problems spend more energy (not less) than their peers more thin, their bodies great need more more energy, not only for work, but also to support excess weight, for this has more sense to consider energy expenditure per kilogram of body mass, according to this children more slender spend more energy even when at rest. This does not mean that children are fat because they have a low metabolism, scientist Michael Goran and his companions, showed that fatty tissue consumes only one third part of the energy consuming muscle fibers and organs such as the brain and liver. This situation gives a response to the power output but that happens with power input?, scientists from the University of Iowa, reviewed feeding children less than 5 years in 3 days and calculated how much energy spent. They concluded that children with problems of obesity ate more, but only proportionally to its size, in fact kilo por kilo of body weight obese children drank fewer calories than thin children, another important finding of this study was that obese children consumian more foods high in fat.