A new study published today in Nature suggests that approximately seven in every thousand morbidly obese people are missing a section of their DNA containing approximately 30 genes, which may be having a dramatic effect on their weight.

Researchers identified the missing genes in teenagers and adults who had learning difficulties or delayed development. They found 31 people who had nearly identical 'deletions' in one copy of their DNA. All of the adults with this genetic change had a BMI of over 30, which means they were obese.

As addressed in other posts, there is a significant difference between "selfishness" and "self-interest".  However, it seems that there is still a general insistence on perpetuating the selfishness perspective.