On our diet topic - I thought this was interesting:

Is Appetite Control All in Your Head?

How much you eat and how much you weigh could be all in your head. An enzyme in your brain, specifically. The Associated Press reports that Harvard University researchers have discovered an enzyme in the brain that performs two tasks: It monitors energy in cells and appears to regulate appetite and weight. The discovery has the potential to lead to new and more effective treatments for obesity.

Called AMP-activated protein kinase, or AMPK, the enzyme is regulated by the hormone leptin, which previous research has linked to appetite suppression. The Harvard scientists found that when AMPK was inhibited in mice, the rodents ate less and lost weight. The opposite happened when AMPK was boosted; they ate more and gained weight.

Lead author Barbara B. Kahn told AP this research identifies a new leptin signaling pathway and a promising new target in humans that will impact drug development and approaches for preventing and treating obesity. This is big news. Currently, there are only a handful of prescription weight-control drugs on the market, and they only produce modest weight loss results. However, the researchers warn that clinical trials on human beings will take years to complete. The study findings were published in the online version of the journal Nature.