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Contemplating devouring that doughnut? Biologist Scott Kanoski’s research shows that eating junk food tricks the brain into wanting to reach for that sugary or fatty treat. By Lizzie Hedrick THE FEEDING CYCLONE When people eat a hot dog just after gobbling down a slice of pizza, it may not be due to lack of willpower. Rather, the brain’s signaling has been hijacked. It’s the “vicious circle” of our Western diet, said Scott Kanoski, assistant professor of biological sciences. Kanoski has published research describing how consistent consumption of saturated fatty acids and refined carbohydrates (i.e., sugars) disrupts the blood-brain barrier, which leads to dysfunction in the hippocampus, a seahorseshaped region of the brain, located in the medial temporal lobe.
HUNGER AND SATIETY CUES Kanoski’s research shows that the hippocampus controls feeding behavior through detection and processing of circulating hormonal signals. The hormones include ghrelin, which signals hunger, and leptin, which signals satiety. His lab’s most recent paper published in Neuropsychopharmacology identifies the hormone glucagon-like peptide-1 (GLP-1) as a key signal that acts in the hippocampus to limit how much food is consumed during a meal and to reduce motivation to eat unhealthy yet tasty food. COMPROMISED HIPPOCAMPUS Once the hippocampus is affected by excess consumption of foods high in saturated
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fat and sugar, its ability to detect and utilize these hormonal signals becomes compromised, Kanoski said. Once this happens, people tend to turn to external cues to determine what, how much and when to eat. But the external cues in our environment contribute to unhealthy and excessive eating. For instance, you may become tempted by vending machines at work and fast food restaurants you see on the way home. FATS, SUGARS OR BOTH? The next step in Kanoski’s research is to determine which foods exactly — fats, sugars or both — are guilty of damaging
the hippocampus, how early in life this cycle begins, and whether or not changing eating habits can reverse this cycle on a neurochemical level. His research also unravels how the hippocampus communicates with other regions in the brain to curb excessive overeating. Kanoski hopes that his research will help send the message that restaurants and companies that produce processed foods must alter their ingredients and people must change their eating habits. “Increased public awareness of the neurological changes caused by the foods we eat, and serve our children, will hopefully help people make different food choices and ultimately transform our eating culture.” Fall 2014 / Winter 2015 39