I have found this interesting research by following the health pages of the BBC. They have reported on studies which have conclusively shown that some people cannot put on weight by overfeeding a normal group of people and also restricting their activity.
One of the subjects said that she vomited the extra food she was supposed to eat and one subject found it hard to eat such large amounts. I also find it hard to eat large amounts of food and this goes all the way back to my childhood so it certainly isn't willpower.
Professor Jane Ogden speculates that genes might have a role to play in what people variously call the "set point" of our weight. There are also variations in the ability of our brown fat stores to dissipate extra energy as heat. Then there are variations in individual metabolic capacity which is a whole other subject to get our head around.
Professor John Blundell at the University of Leeds has also reported on the effects of feeding a high fat diet to male subjects which have shown some interesting and unexpected results.
So where does this leave us in our understanding of people who say "I put on weight if I just look at a packet of crisps!"
They might be right. Psychologists have identifed a form of thinking called "Thought Shape Fusion" thinking where a person thinking about forbidden food irrationally believes that they are going to gain weight. This is turn makes them feel helpless and ashamed, a sure trigger for having the crisps to console themselves or to block the horrible feelings that emerge.
To read the article to go http://news.bbc.co.uk/1/hi/magazine/7838668.stm. And, if you want to learn how to change the subtle and insidious thinking that cuases weight gain in some people and not in others, consider coming on our BPS Approved eating disorders training course seecheck it out at http://www.eating-disorders.org.uk/