The Crux of it is...
Perhaps the most basic question is, "Why are some people hungry even after they’ve eaten enough to maintain "normal" or "average" body weight?" Now we’re, if you’ll forgive me, cooking.They Don't...?
The last would appear to be the crucial issue, wouldn’t it? Many overweight people are surprised to learn that the skinny persons of the world do not generally leave the table hungry, but simply quit eating because they aren’t hungry anymore at calorie levels that don’t add to their weight. Skinny persons likewise don’t get up in the middle of the night to eat, as a rule, because they’re simply not hungry enough to do so. Granted, even skinny people will often eat something even if they’re not hungry just for the pleasure of the taste, but most skinny people don’t consistently eat a lot in these circumstances and they don’t do it regularly. Further, skinny people who eat beyond their habitual calorie levels for a few days often find that their appetites are depressed for several days after.What is appetite, anyhow...?
There is poor understanding of all of the determinants of appetite. We know many things; we don’t begin to know enough. The fact everyone knows, heavy or not, is how hard it is to get past the refrigerator when you feel the saliva pooling in your mouth, when you become acutely aware of the hollowness in the back of the throat and in your stomach. Ultimately, it seems likely that obesity will not be fully defeated until many more of the determinants of appetite are uncovered and brought under medical control.A recent count of genes and gene neighborhoods that impact obesity was 130 and climbing (Vogel, The Skinny on Fat). Appetite is certainly your experience of the effects of those genes on your physical and mental processes. The good news in recognition of the genetic underpinning of obesity is that drug companies—now that researchers are no longer focused on character disorder as an explanation-- are beating themselves into a froth to come up with drugs to combat it. The bad news is that with all the combinations of even the known 130 genes that people can have, it is very likely that obesity will be due to many different mechanisms in different people.
So, That makes it very unlikely that a single "magic bullet" will be found to treat everyone. Just as with high blood pressure where many different drugs are necessary to treat the condition in different people, so it is proving to be with obesity. We can hope however that a relatively few genes will be the main culprits in most of the population and that effective modifiers for more of those than now exist will be developed in the near future.