Scientists suspect that one element of the obesity epidemic is that the brains of obese people respond differently to images of delicious, calorically dense foods. Obese individuals’ brains seem to light up at the sight of donuts, pizza, and other calorie bombs, even when they’re no longer hungry.
Some studies have suggested that this heightened activity might predispose people to overeating. Today, nearly 40 percent of American adults are obese, and obesity is predicted to become the leading cause of cancer among Americans, replacing smoking, within five or 10 years. (It’s still not clear yet which comes first—the obesity or the overactive brain activity.) “Part of the reason for the obesity epidemic is that people eat when they’re not hungry,” says Elizabeth Lawson, an associate professor of medicine at Harvard Medical School and a neuroendocrinologist at Massachusetts General Hospital.
A remedy for this over-activation in the brain might come from an unexpected source: oxytocin, the brain chemical often associated with love and social relationships. Oxytocin is sometimes called the “love hormone” because it’s released during sex, childbirth, and breastfeeding. People who are in the early stages of falling in love have higher levels of oxytocin than normal. The drug ecstasy also increases concentrations of the hormone in the blood.
Oxytocin has a variety of other surprising functions. A form of the chemical, Pitocin, induces labor, and another form might help treat stomach pain. Early studies have suggested that the hormone might boost social skills among kids with autism. Now Lawson and other researchers are investigating whether oxytocin might also prevent overeating.
Lawson and her colleagues recently showed images of high-calorie foods to 10 overweight and obese men. She found that the regions of the brain involved in eating for pleasure lit up when the men viewed the images. A dose of oxytocin, compared with a placebo, weakened the activity in those regions, and it also reduced the activity between them. Meanwhile, oxytocin didn’t have that effect when the men viewed images of low-calorie foods or household items. Lawson’s colleagues presented the research, which has not yet been published in a peer-reviewed journal, last month at Endo 2019, the Endocrine Society’s annual meeting.
“One of the key ways oxytocin works in limiting the amount of food that we eat is that it speeds up the satiety process, or reaching fullness,” says Pawel Olszewski, an associate professor of physiology at the University of Waikato, in New Zealand, who was not involved with Lawson’s study. “Then, oxytocin works through brain areas that are associated with the pleasure of eating, and it decreases our eating for pleasure.” (thebrighterside.news)
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