Remember when we talked about the discovery of the obesity gene in certain mice, we said that the protein made by that gene was called Leptin. The mice who were fat did not make Leptin or they made a flawed version of it. This really was a major breakthrough in the science of fat because for the first time a specific cause that has nothing to do with diet and exercise was identified - in those mice.

The discovery of Leptin unleashed a feeding frenzy of research that shows how important this subject is to everybody.

In those famous mice, the weight distribution curve has two humps. This makes sense because they have the good gene or the bad one and they are otherwise almost identical. That is how they found the gene. In humans however, there is a normal bell shaped curve for weight. So we know right away that humans don't have just one gene controlling their weight. When there is a single gene for something like hemophilia A, you either have it or you don't. There