Getting The Full Feeling

After finishing my evening meal I again immediately wanted a PBJ. Like last time I talked myself out of it. I even stared down a jar of jelly in the fridge before I gave it up. It did get me thinking about the subject of fullness again, however.

What makes the body give off the fullness signal that it's time to stop eating? Is is a physical reaction from GI track to brain that says - whoa, hold on, that's enough - or is it something else?

I did manage to find an interesting study about the subject of feeling full or satiated. What was curious about the study was that it pointed to both neurological and hormonal triggers. Basically the area of the brain called the left posterior amygdala switches on when people feel full. The study found that area switches on less in more overweight/obese people than it does in thinner folks. To go along with that, the hormone ghrelin also show up when people feel full. The larger the increase in ghrelin levels, the more active the left posterior amygdala. Here's the link to the study.

ABC also had an interesting article on ghrelin. No new ground plowed as far as research - reiterates waiting 20 minutes between servings, but it had some suggestions on what foods suppress ghrelin production more than others:

Nicole Beland, a senior contributor at Women's Health magazine, says you can suppress ghrelin by eating certain foods, so you will then feel full. Carbohydrates and lean protein have been found to slow the production of ghrelin, while foods that are high in fat do not.

Hang on now. One study talks about increasing levels of ghrelin being linked to the amygdala and the other talks about slowing the production of ghrelin. Which is it, or am I misunderstanding? The Wikipedia article on ghrelin also talks about decreasing ghrelin production as being good for weight loss/hunger suppression. So can there be an increase in levels with a decrease in production? I'm really stumped by the relationship. From my googling around it would appear that there really isn't a clear definition on what causes the full feeling.

Just as I was about to close this entry down, I ran across an article on Healthy Satiety. Explains thing pretty well and has some interesting suggestions.