I don’t think anything in that posts suggests a “psychological” view of obesity set points. The experiments where people were fed a certain diet (whose amount of calories they didn’t know, and presumably had no access to scales) yet still felt a strong urge to eat the amount of calories that returns them to their set point seems strongly against that explanation. Then the rat studies help clarify that in even more controlled conditions. It would be very strange for set points in humans and rats to have the same properties, but for the mechanisms to have nothing to do with one another.
Feelings of satiation are caused by many factors, including neural signals from the gut (which supposedly is not enough to explain the alleged obesity set-point), hormones due to blood levels of carbohydrates, and also blood levels of amino acids and lipids. In addition, they are caused by levels of insulin, glucagon, and cholecystokinin, among others.
The desire to eat more may simply be because the rat wants to maintain the levels of these hormones that they’re used to. There is absolutely no reason to think (based on these experiments, at least) that there’s a set-point that is based on ‘healthy weight for your height/age, plus or minus a genetic factor’. In fact the very article you linked strongly agrees with this viewpoint and disagrees with your view.
The reason I mentioned the bait-and-switch is because the mechanisms controlling eating in humans are very likely, in my opinion, to be different from rats. Note that this isn’t the same as saying the reasons are disjoint. It could be that we have the same underlyling mechanisms as rats, but also a large psychological component on top of that, that effectively prevents being able to directly compare rats and humans.
That wasn’t my impression. See for example the paragraphs about the rats given foods of different caloric densities.
We were talking about people. No bait-and-switch, Yvain!
I don’t think anything in that posts suggests a “psychological” view of obesity set points. The experiments where people were fed a certain diet (whose amount of calories they didn’t know, and presumably had no access to scales) yet still felt a strong urge to eat the amount of calories that returns them to their set point seems strongly against that explanation. Then the rat studies help clarify that in even more controlled conditions. It would be very strange for set points in humans and rats to have the same properties, but for the mechanisms to have nothing to do with one another.
Feelings of satiation are caused by many factors, including neural signals from the gut (which supposedly is not enough to explain the alleged obesity set-point), hormones due to blood levels of carbohydrates, and also blood levels of amino acids and lipids. In addition, they are caused by levels of insulin, glucagon, and cholecystokinin, among others.
The desire to eat more may simply be because the rat wants to maintain the levels of these hormones that they’re used to. There is absolutely no reason to think (based on these experiments, at least) that there’s a set-point that is based on ‘healthy weight for your height/age, plus or minus a genetic factor’. In fact the very article you linked strongly agrees with this viewpoint and disagrees with your view.
The reason I mentioned the bait-and-switch is because the mechanisms controlling eating in humans are very likely, in my opinion, to be different from rats. Note that this isn’t the same as saying the reasons are disjoint. It could be that we have the same underlyling mechanisms as rats, but also a large psychological component on top of that, that effectively prevents being able to directly compare rats and humans.