A new animal study from the University of Florida, published August 2008 in the American Journal of Physiology — Regulatory, Integrative and Comparative Physiology, found that rats became leptin-resistant after being fed a high-fructose diet for six months. Leptin is the appetite-controlling hormone and leptin resistance has long been linked to obesity. This study and a number of other studies have shown that overconsumption of fructose may be an important factor in the United States’ obesity epidemic. This new study is the first to link fructose and leptin resistance.
The fructose-fed rats gained considerably more weight than rats that never received fructose when both groups of rats were switched to a high-fat diet.
“The surprising finding here was that increasing the amount of fructose in the diet without increasing the amount of calories led to leptin resistance and later exacerbated obesity when paired with a high-fat diet,” study senior author Philip J. Scarpace, a professor of pharmacology and therapeutics in the College of Medicine, said in a university news release.
“[Fructose] blocks leptin action most likely by blocking leptin entry into the brain,” study author Alexandra Shapiro, an assistant scientist in the department of pharmacology and therapeutics, explained in the news release.
“If these findings are applicable to humans, then there could be consequences of eating a diet high in fructose, but only if you also consume an excessive amount of calories,” Scarpace said.