Serum and DNA samples: Samples of serum will be frozen and stored for future testing of new and emerging cardiovascular risk factors. DNA samples will be frozen and stored to identify genetic markers of diet response. We will use these samples to determine the possibility that the common genetic variant ENPP1 K121Q could predispose diabetic and metabolic syndrome subjects to respond better to weight loss intervention than those who have the common variant K121K. Similarly, other genetic variants that associate with obesity and insulin resistance may change susceptibility to weight loss in different directions. If at any time during the study a participant decides they do not want their serum samples to be stored they may have them destroyed