The study uncovered the surprising finding that obese people may receive less pleasure than average people when eating desired foods. In the average person chocolate stimulus releases dopamine in the brain which is translated as pleasure and satisfaction. People who have a gene variant simply do not release as much dopamine when stimulated with a typical trigger such as chocolate.
A year after the beginning of the study, women with the gene variant had put on more weight than women without the gene. The study has interesting implications. Perhaps people who overeat get less pleasure from rich foods than their thinner counterparts, and thus eat more to make up a "pleasure gap". "If you look at the brain response when people are about to get the milkshake, obese individuals show greater activation of the reward circuitry, not less," the researchers say.
"So, ironically, they expect more reward but seem to experience less." Thus once a craving starts it is hard to satiate it. The researchers suggested the best way to avoid the conundrum is to go cold-turkey. Stop eating a specific food for six-weeks (e.g. chocolate) and the cravings will go away.