A quick hit on an interesting bit of new research, published in the Journal of Clinical Investigation.
Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans
Studies in animals have documented that, compared with glucose, dietary fructose induces dyslipidemia and insulin resistance. To assess the relative effects of these dietary sugars during sustained consumption in humans, overweight and obese subjects consumed glucose- or fructose-sweetened beverages providing 25% of energy requirements for 10 weeks. Although both groups exhibited similar weight gain during the intervention, visceral adipose volume was significantly increased only in subjects consuming fructose. Fasting plasma triglyceride concentrations increased by approximately 10% during 10 weeks of glucose consumption but not after fructose consumption. In contrast, hepatic de novo lipogenesis (DNL) [RN: liver making fat] and the 23-hour postprandial triglyceride AUC were increased specifically during fructose consumption. Similarly, markers of altered lipid metabolism and lipoprotein remodeling, including fasting apoB, LDL, small dense LDL, oxidized LDL, and postprandial concentrations of remnant-like particle–triglyceride and –cholesterol significantly increased during fructose but not glucose consumption. In addition, fasting plasma glucose and insulin levels increased and insulin sensitivity decreased in subjects consuming fructose but not in those consuming glucose. These data suggest that dietary fructose specifically increases DNL, promotes dyslipidemia, decreases insulin sensitivity, and increases visceral adiposity in overweight/obese adults.
Wow, that's quite an indictment, as well as a contrast. So, fructose makes your liver create new fat, gives you more small dense LDL and oxidized LDL — the worst, true artery "clogging" kind — and gives you a fat belly.
Think about that next time you purchase products that contain HFCS, which just about all processed food does.
It's useful to note that primitive man in most environments would probably have had quite a bit more access to higher glucose concentrations (tubers and such) than fructose (fruits, honey, and so on) most of the time. It could be that we specifically evolved to put on fat in the late summer and fall in preparation for winter, and that fruit was a primary vehicle for accomplishing that.
Perhaps potatoes aren't as bad as thought, and maybe fruit isn't as good. I like to limit both, but if I had to choose, I'll take some potato with my meat.
Later: Hadn't seen this yet, but Stephan blogged about this study.