Hunger and obesity

Robert, a 25 year old Hispanic male, is 230 lbs overweight. Because of health reasons, Robert has tried exercising and dieting but the most amount of weight he’s lost is 5-10 lbs. Even when he’s lost weight, he always gains it back and some more. Robert lives at home with supportive parents who have tried to help him loose weight throughout his entire life, as this has been an issue for Robert since childhood. Robert feels frustrated and strongly believes that there must be something wrong with his body because no one else in his family is overweight. Robert claims he’s always hungry and whenever he has tried fasting, he feels very anxious and ends up eating more.
Assuming the role of a Pure researcher, which hormone(s), neurotransmitter(s), and brain part(s) would you be interested in researching to help Robert figure out if, in fact, something is wrong with his body? Please be sure to explain the role of each hormone, neurotransmitter, and brain part in Robert’s insatiable hunger and obesity.