A new study suggests fat people have less grey and white matter in a significant network of their brains -- though not in the brain overall -- than people who are not fat. The article suggests this means that they are less "intelligent" when it comes to making good food choices.
I'm not buying it, if only because the measure they used was BMI. Someone who has a high BMI because they are a weightlifter is all about smart food choices. It takes considerable attention to ensure you get enough protein to maintain large muscles. The suggestion that BMI correlates with weakened self-control over food choices isn't adequate. (I doubt that they really used only BMI, anyway. If they wanted to study 'fat people,' they doubtless used an informal visual evaluation to determine which high-BMI candidates to include.)
Nor am I ready to buy off on the claim that we know exactly what part of the brain always and everywhere handles this or that function of the mind.
However, a follow-on study might be interesting if the study were done over a period of years, especially tracking thin people of whom some became obese. I'd be interested to know if the weakening of this sector proceeded or followed the increase in weight.