Some of you may have noticed the thread regarding stomach surgery to assist people that are obese lose weight. It got me thinking about the opposite problem. People who are underweight. I'm not necessarily talking about anorexia. Just people who have a hard time putting on weight. It can be their genes, predisposing them to a slim shape and low mass. Or maybe incorrect intake of the required nutrients to sustain the appropriate mass for that body type? There are people, who have a huge intake but just can't seem to put any weight on. Is it the fast metabolism? Is it something else? Just thought this topic was worth some conversation.