I don't know what turned the tide in research but it seems lately there have been quite a few startling discoveries about obesity and the genetic aspect thereof. Last month there was a report on research at UT Southwestern Medical Center on the discovery of a gene called adipose, that appears to make some people naturally heavier than others.
Now, researchers at the University at Buffalo have found more possible genetic reasons for overeating and obesity. According to their report, people who have genetically lower dopamine levels tend to eat more, and find food more reinforcing (rewarding). Dopamine is a neurotransmitter that helps make behaviors and substances more rewarding. Having fewer dopamine receptors means that you would have to eat more of a favorite food in order to experience the "feel good" reward from it.
The researchers caution that not all people with this genotype will be obese nor does having the genotype cause obesity in and of itself.
"Behavior and biology interact and influence each other," says lead author, Leonard Epstein, PhD. "The genotype does not cause obesity; it is one of many factors that may contribute to it. I think the factors that make up eating behavior are in part genetic and in part learning history."
The study article, "Food Reinforcement, the Dopamine D2 Receptor Genotype, and Energy Intake in Obese and Non-obese Humans" is published in the October issue of Behavioral Neuroscience.