A recent study that has been covered in both the New York Times and Psychology Today (among other places) has been confirming something I recognized a long time ago about overweight people. That is, our bodies don't talk to us the same way about eating as people who are thin or of average weight, and there's not much we can do about it.
The information is complicated and I'm not going to regurgitate the contents of the articles when you can find them and read them for yourself. Also, frankly, I find people who blog about the contents of articles to be pretty lame. If you don't have something to say, then you shouldn't have a blog, not choose to re-purpose content from news sources.
At any rate, one of the points discussed in those articles is the fact that people who are overweight aren't told that they are full until they have already over-eaten. There is a chemical in your brain called leptin which signals satiety and cues you to put down the fork. People who are prone to be fat (something which is decided in your mother's womb, according to the studies) appear to need far higher levels of leptin for their brains to recognize that eating should stop.
This is something which I have noticed in myself for quite some time, but have had difficulty acting on. When my husband and I have a meal, I often still feel hungry at the end of the meal for as long as an hour afterward. In the past, this has often cued me to keep on eating while he has already stopped because he's full. The method I have started to use to try and stop this is to focus on how my stomach feels rather than on what my brain is telling me. That is, I think about the fact that there is food in my stomach now and it is enough. I can't say that is 100% successful as a technique, but it works coupled with other behavioral modification practices like immediately washing the dishes, putting away leftovers, or generally engaging in some activity which prohibits me from continuing to eat.
This method works adequately when I eat at home, but the situation is quite a bit more complicated if one eats out a lot. Eating out almost certainly is going to compel one to eat too much for a variety of reasons. First of all, the food is often better or at least more interesting than what you eat at home. Second, it's usually plentiful and there is the sense that whatever you don't eat will be wasted, and third, it's expensive so you don't want to let it go to waste. Finally, if you're in a restaurant, you don't have a way to distract yourself from the food or the capacity to simply walk away the instant you have eaten "enough". You're just sitting there with tasty food in front of you and your brain is saying, "I'm not full yet."
I also wonder if part of the reason we eat more now is the loss of the sit down family meal as a part of our culture. If you sit down to eat with other people, there are a variety of factors that can influence how much you eat. You are talking more between bites so it takes longer to finish the meal (which gives even those who need more leptin a chance for their brain to reach the point where it says, "I'm full."). Also, being around other people, even your family may cause people who are inclined to overeat to be more modest. As I've mentioned in a previous post, fat people don't like to be seen as eating a lot in front of others. There's also the fact that the food is more mundane and people eat less if they don't find the food greatly appealing. Part of one of the articles I referenced says something about mice overeating on a chocolate supplement they liked, but cutting way back once their routine diet was reintroduced.
The articles I'm referencing talk about the question of whether the obesity epidemic in America is linked to unhealthy food or not because the food has never been particularly healthy. If you look at the Gallery of Regrettable Food, which shows cooking information from the 50's and other eras, you can see that food certainly was not great even when people were thin. My sense is that a lot of the obesity epidemic is linked to the great increase in eating out or frozen and prepared foods as a result of women's roles changing from homemaker to working outside the house as well as the decrease in manual labor and increase in sedentary recreational activities like television watching and computer use.
At any rate, thin people take their ability to stop eating for granted and one of the reasons they judge fat people is that they have no idea that we live a very different life than they do. They effortlessly resist whereas we have to focus very hard and trick ourselves if we don't want to overeat all of the time. The effort is not inconsiderable, though I'm guessing it is possible since I've had some success with it so far.