I hate poachers and I love animals, but this guy I hard not to love and he does make a good villain. Utterly cruel and psychotic, he loves killing and is greedy. In fact, he's so psychotic that he attempts to feed Cody to the crocodiles when he no longer has use for him.
The first is leptin, which is a hormone secreted by your fat cells that acts as an appetite suppressant. Leptin levels peak when you fill up on food. So, when you eat a lot, your appetite goes away. If you ever said, 'I am so full I couldn't eat another bite,' then in that moment, your body was flooded with leptin.
Leptin is a hormone that is pumped out by your fat cells (Yes, they do more than just give you cellulite!). Leptin has a specific action in the brain (it works on your hypothalamus) to control your metabolism, and your appetite. You see: We evolved with leptin as a way for our fat cells to communicate with our brain.