Randy asked the BioTAP students to develop a brief presentation that would propose a research program to develop a new drug to influence the regulation of metabolism. The goal was to have the students do some research to understand metabolism better. One group looked at ghrelin and found 
this great paper that shows why diets are so miserable. Ghrelin is a hormone that makes you feel hungry. Here's a graph that shows ghrelin levels before and after dieting.
When you start dieting, your average ghrelin levels are about as high as your peak levels before dieting. No wonder diets almost never work. The article goes on to talk about gastric bypass surgery (which, for some unknown reason causes ghrelin levels to drop to very low levels and to not have oscillations associated with meals). I think I'll stick with low-carbs diets, myself.