Fructose, a form of sugar found in products such as high-fructose corn syrup, causes excess hunger and subsequent overeating, according to a new report released Wednesday.
The study, conducted by Yale University School of Medicine, finds that fructose causes reactions in the human brain—such that one's appetite is increased—convincing the body it needs to consume more food than it actually does.
High-fructose corn syrup, the almost ubiquitous sweetener found in packaged and processed foods in the US, and commonly labeled a leading cause of obesity in the country, contains a higher proportion of fructose than most other sweeteners including table sugar, which contains both fructose and glucose.
Scientific American explains:
Fructose and glucose look similar molecularly, but fructose is metabolized differently by the body and prompts the body to secrete less insulin than does glucose (insulin plays a role in telling the body to feel full and in dulling the reward the body gets from food). Fructose also fails to reduce the amount of circulating ghrelin (a hunger-signaling hormone) as much as glucose does.
The study, which was conducted on adult volunteers using fMRIs (functional magnetic resonance imaging) to measure responses to fructose in the brain, concludes that "consumption of fructose compared with glucose resulted in a distinct pattern of regional CBF and a smaller increase in systemic glucose, insulin, and glucagon-like polypeptide 1 levels." In other words, ingredients such as high-fructose corn syrup makes us desire more food and beverages when our body doesn't actually need them.
Recent "food processing and economic forces," which have increased America's consumption of high fructose corn syrup, is "indeed extending the supersizing concept to the population's collective waistlines," according to Jonathan Purnell, of the Division of Endocrinology, Diabetes, and Clinical Nutrition, and Damien Fair, of the Department of Behavioral Neuroscience, both of Oregon Health & Sciences University in Portland.
"The reality, however, is that hunger and fullness are major determinants of how much humans eat, just as thirst determines how much humans drink. These sensations cannot simply be willed away or ignored."