....Lipogenesis increased significantly when glucose was replaced with fructose on a gram-for-gram basis in energy drinks consumed by six healthy volunteers, researchers here found.
Conversion of fructose to lipid occurred quickly, usually within four hours after ingestion, Elizabeth Parks, Ph.D., of the University of Texas Southwestern Medical Center, and colleagues reported in the June issue of the Journal of Nutrition.
Moreover, consumption of a high-fructose drink for breakfast increased liver-mediated fat storage after lunch, the researchers said.
"Our study shows for the first time the surprising speed with which humans make body fat from fructose," said Dr. Park. "Once you start the process of fat synthesis from fructose, it's hard to slow it down."
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"The message from this study is powerful because body fat synthesis was measured immediately after the sweet drinks were consumed," Dr. Parks said. "The carbohydrates came into the body as sugars, they liver took the molecules apart . . . and put them back together to build fats. All this happened within four hours after the fructose drink. As a result, when the next meal was eaten, the lunch fat was more likely to be stored than burned."
The message should not be misconstrued by people who are trying to lose weight, she continued. Specifically, they should not eliminate dietary fruits, which have high fructose concentrations.
Overeating and excess caloric consumption remain the principal drivers of weight gain and obesity, she concluded.
Journal of Nutrition
Parks EJ, et al "Dietary sugars stimulate fatty acid synthesis in adults" J Nutr 2008; 138: 1039-1046.