@pastanaga - It also helps to demonstrate why scientists haven't managed to find a magic pill that controls appetite and weight gain yet. Most people believe that having a full stomach is what makes you feel full, but it's actually blood sugar levels. And messing around with blood sugar levels can be dangerous.
As it says in the article, if someone has very low blood sugar levels they can go into shock or die very quickly and glucagon is used by the body to adjust for that (although not quickly enough, or we wouldn't need to use injections to help people). It's just one of lots of different hormones that control blood sugar and fat storage and tipping even one out of whack could kill someone. So, it's a dangerous thing to mess with.
I have no doubt, though, that they will eventually come up with weight loss medication that really works.