Brain Eating Zombies of the Day

Kenneth Mackie et al.

Key Shift in Brain That Creates Drive to Overeat Identified

The switch involves receptors that trigger or inhibit the release of the orexin A peptide, which stimulates the appetite, among other behaviors. In normal-weight mice, activation of this receptor decreases orexin A release. In obese mice, activation of this receptor stimulates orexin A release.
Using mice, this study found that in obesity, CB1 cannabinoid receptors become enriched on the nerve terminals that normally inhibit orexin neuron activity, and the orexin neurons produce more of the endocannabinoids to activate these receptors. Activating these CB1 receptors decreases inhibition of the orexin neurons, increasing orexin A release and food consumption.

Well that explains the effects of medical marijuana.  In mice.  Maybe.  But more orexin production does NOT explain obesity in humans, as evidenced by the fact that Narcoleptics - who have no orexin- have an extremely high incidence of binge eating and obesity.   Geez louise, do your homework...

An emerging idea, Mackie said, is that this network is reset during obesity so that food consumption matches maintenance of current weight, not a person's ideal weight. Thus, an obese individual who loses weight finds it difficult to keep the weight off, as the brain signals the body to eat more in an attempt to return to the heavier weight.

Yes, well I will have to tell him he's wrong about that.
There is no frakkin set point.  We just get fatter, period.