Credit: Boston Children's Hospital. Three sibling mice. The one on the left has a genetic defect that causes it to grow fat even though it was given the same diet.

A recent report in Science Magazine shows that mice that have certain genetic defects can eat exactly the same healthy diet as their genetically normal siblings, yet still gain weight to the point of obesity. This is further evidence that obesity is not necessarily about gluttony and lack of will, but about your bodys metabolic control system.

Gina Kolata of the New York Times wrote an excellent lay summary of the research.