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Previous research by MU’s Heather Leidy, including a study featured in Illumination’s Spring/Summer 2012 issue, have shown that eating a healthy breakfast, in particular one high in protein, plays an outsized role in keeping subsequent food cravings under control. Now she’s closing in on determining why.
In findings published late last year, Leidy, an assistant professor of nutrition and exercise physiology, Matthew Will, an associate professor of psychological sciences, and Heather Hoertel, an MU graduate student, determined that the protein-rich breakfasts consumed by their test subjects — 19-year-old women who struggled with their weight — correlated positively with elevated levels of a chemical marker associated with dopamine, a neurotransmitter that helps control the brain’s reward and pleasure centers. Sustaining levels of this “reward” chemical, the scientists say, may be key to reducing food cravings and subsequent overeating later in the day. It’s an insight that could, in turn, lead to improvements in obesity prevention and treatment.
“Our research showed that people experience a dramatic decline in cravings for sweet foods when they eat breakfast,” Leidy says, adding that high-protein breakfasts also reduced cravings for savory, high-fat foods. Skipping breakfast, a behavior many of her youthful research subjects are prone to, caused “cravings that continue to rise throughout the day,” she says.
The study determined dopamine by measuring homovanillic acid (HVA), the main dopamine metabolite. Eating initiates a release of dopamine, which stimulates feelings of food reward. The reward response is an important part of eating because it helps to regulate food intake, Leidy says.
“Dopamine levels are blunted in individuals who are overweight or obese, which means that it takes much more stimulation – or food – to elicit feelings of reward; we saw similar responses within breakfast-skippers,” says Leidy. “To counteract the tendencies to overeat and to prevent weight gain that occurs as a result of overeating, we tried to identify dietary behaviors that provide these feelings of reward while reducing cravings for high-fat foods. Eating breakfast, particularly a breakfast high in protein, seems to do that.”
The study appeared in the Nutrition Journal.