Weight loss is always a popular topic of New Year’s resolutions, talk shows and self help guides. However, recently concern has turned toward a more severe form of weigh gain, obesity. It seems one cannot open a newspaper without reading about it. In fact, in 2000, Philadelphia was the fattest city in the United States and in 2005 the third fattest city. (1) Clearly, obesity is a pervasive problem, a disease occurring with alarming frequency. Being obese, having a body mass index of over 30, (2) is associated with risk factors such as high blood pressure, coronary artery disease, sleep apnea, cancer, diabetes, and death: 300,000 deaths a year in the United States are linked to obesity. (3) In 1998, the Nation Institute of Health (NIH) found that 55% of the United States population is overweight, and estimated that in 2004 this had climbed to two-thirds of adults in the US. These statistics have grabbed the attention of both the NIH and the World Health Organization (WHO), which composed a Global Strategy on Diet, Physical Activity, and Health in 2004. (4) While many factors and causes are being investigated for this growing problem, the science behind addiction can help us understand this disease.