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Rational Or Emotional? Your Brain On Food
People overestimate their ability to control their impulses.
The study below found increased neural activity in areas of the brain known to control food intake when patients who lost weight were exposed to food (because leptin -a hormone that helps control appetite-dropped). When leptin was injected into the volunteers (to reach a normal level) the brain acted and behaved normally. Fascinating!
One of the hormones that play a role in controlling appetite in the body is called leptin. After significant weight loss, leptin levels drop. This seems to signal to the brain a need to seek more food.
Rosenbaum and his colleague Joy Hirsch, a neuroscientist at Columbia University Medical Center, designed an experiment to better understand the relationship between the brain, leptin and weight-loss maintenance.
They recruited overweight volunteers who agreed to a calorie-restricted diet aimed at shedding 10 percent of body weight. Using fMRI scans, the researchers looked at how the volunteers' brain responses to seeing food changed after weight loss.
Still Emotionally Attached
During their study, Hirsch and her colleagues found some interesting patterns of neural activity in their volunteers after they'd lost weight.
For instance, there was more blood flow to areas of the brain known to be involved in the emotional control of food intake, such as the brainstem and parahippocampal gyrus.
But here's the fascinating part: When they restored leptin to these volunteers by giving them injections of the hormone, the brain response changed. When they saw food, there was more activity in brain areas associated with conscious decisions.
“It's a feedback mechanism,” says Rexford Ahima of the University of Pennsylvania. Leptin signals the brain; when there's a deficiency of the hormone, the areas of the brain associated with reward-seeking become more active.