Being Fat Needn't Be All Bad News

It is thought that one reason over eating causes insulin resistance is that fat is deposited in organs of the body, such as the liver, rather than in the fat tissue. This idea is now supported by the work of Phillip Scherer and colleagues at Albert Einstein College of Medicine, New York, who have shown that insulin resistance in mice is not determined by how fat they are but rather where the fat is stored.

Mice that are obese because they lack leptin (ob/ob mice) become insulin resistant. In the new study, researchers show that if ob/ob mice are engineered to express adiponectin they do not become insulin resistant.

However, these mice were morbidly obese and the mass of their fat tissues was much increased compared with normal ob/ob mice. The authors therefore suggest that an inability to maintain high levels of adiponectin might be what causes insulin resistance in individuals who over eat because it would mean that the excess food they consume is stored in regions of the body other than the fat tissues.

Article: Obesity-associated improvements in metabolic profile through expansion of adipose tissue