Research has demonstrated that excessive intake of fructose can induce leptin resistance, and in combination with a high-fat, high-calorie diet, can lead to becoming overweight.
Previous studies have already shown that leptin resistance can lead to rapid weight gain on a high-fat, high-calorie diet, but this is the first study to show that leptin resistance can develop as a result of high fructose consumption, and that leptin resistance can develop with little indication that it is happening.
Leptin is a hormone that plays a role in helping the body to balance food intake with energy expenditure. Leptin resistance is when the body no longer responds to the leptin it produces. Leptin resistance is associated with weight gain and obesity in the face of a high-fat, high-calorie diet.
Fructose is the sugar found in fruit, but normal consumption of fruit is not the problem. Sugar and high-fructose corn syrup are about 50% fructose and are common ingredients in many foods and beverages, which leads to excessive fructose consumption.
In this study. The University of Florida researchers fed two groups of rats the same diet over a period of six months; one group consumed a lot of fructose while the other received no fructose.
The only difference at the end of the six months was that the rats on the high-fructose diet had higher levels of triglycerides in their blood.
However, after administering leptin to both groups, the researchers discovered that the rats on the high-fructose diet were leptin resistant, that is, they did not lower their food intake when given leptin. The no-fructose rats responded normally to leptin by eating less. They also discovered that the leptin resistant rats ate more and gained much more weight and fat than the leptin responsive animals on the fructose-free diet.
The researchers say the study suggests it is the interaction between consumption of large amounts of fructose-containing foods and eating a high-fat, high-calorie diet that produces the weight gain.
Other studies have shown that elevated triglycerides impair the transport of leptin across the blood brain barrier, and the researchers hypothesize that the elevation in triglycerides produced by fructose prevented leptin from reaching the brain. If leptin does not reach the brain, the brain will not send out the signal to stop eating.
References:
1. Alexandra Shapiro, Wei Mu, Carlos Roncal, Kit-Yan Cheng, Richard J. Johnson and Philip J. Scarpace. Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding. University of Florida College of Medicine. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. October 2008.
2. Image by RayDa54
