Wikipedia- "Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847.[3] Pure, dry fructose is a very sweet, white, odorless, crystalline solid and is the most water-soluble of all the sugars.[4] From plant sources, fructose is found in Honey, tree and vine fruits, flowers, berries and most root vegetables. In plants, fructose may be present as the monosaccharide and/or as a component of sucrose. Sucrose is a disaccharidewith a molecule of glucose and a molecule of fructose bonded together with a glycosidic linkage. Most modern fruits and vegetables have been bred to have much higher sugar content than the wild plants they are descended from.
Commercially, fructose is usually derived from sugar cane, sugar beets and corn and there are 3 commercially important forms. Crystalline fructose is the monosaccharide, dried and ground, and of high purity. High-fructose corn syrup (HFCS) is a mixture of glucose and fructose as monosaccharides. Sucrose is the third form. All forms of fructose, including fruits and juices, are commonly added to foods and drinks for palatability, tasteenhancement and improved browning of some foods, such as baked goods." I spent some time watching Sugar: The Bitter Truth on utube this week. Throughout the video Robert Lustig attempts to identify the risks of eating products with fructose added. Here are some interesting points about this sugar and how it metabolizes in comparison the carbohydrate/sugar, glucose."
Glucose vs Fructose a biochemical point of view.
Metabolism is completely different from fructose and glucose.
Glucose are natural sugars found in starchy carbohydrates. Every cell in your body uses glucose. 80% of calories from glucose can be used by your body. The remaining 20% will go to the liver. Once in the liver it stimulates insulin and eventually stores the calories as glycogen. You can store an unlimited amount of glucose as glycogen in your liver. (hence carb loading in athletes) The stored glucose eventually gets converted into fat.
Sucrose(table sugar) or High fructose corn syrup are both half glucose and half fructose. In other words, High Fructose Corn Syrup is 55% Fructose, Sucrose is 50% Fructrose. The are created equal and both equally as bad for you. Only the liver can metabolize fructose so ALL calories from the fructose go directly to your liver to metabolize (none are given to your cells like the 80% from glucose). Fructose does not stimulate insulin (when insulin doesn't go up, leptin doesn't go up and your brain never gets the signal that you ate something so again, you will eat more). In the liver the fructose creates Uric Acid which causes hypertension. Finally fructose stimulates enzymes for new fat making. 30% of fructose calories will end up as fat. It has been shown that fructose consumption will change the way your brain recognizes energy. In the end-without the insulin stimulation your brain will think you are starving even though you have more and more fat cells from eating the fructose.
How can you avoid these negative effects of fructose?
Find your fructose in nature.
Where ever there is fructose in nature, there is a ton of fiber. Before food processing we would get our fructose from fruits and vegetables and consume and average of 15 grams of fructose a day. We would also consume on average 100-300 grams of fiber a day. Today we consume and on average 72 grams of fructose and a meager 12 grams of fiber per day. When you eat your carbohydrate with fiber it limits the amount of fructose you will take in and it will give you an essential nutrient that you need anyway. There is WAY more to the story about fiber and it's connection with the metabolism of carbohydrates-but that's another topic that I'd like to look more into. They don't go in detail enough about it here.
Exercise to burn carbohydrates.
If you exercise to burn the stored glucose in your liver before it is turned into fat, counting calories and additional weight gain will be obsolete. In essence exercise will help raise your metabolism and avoid extra fat cells. If you eat "good" carbs/sugars you will only need to burn the 20% of the calories that make it to the liver. If you eat lots of products with fructose, you will need to burn a lot more calories.
As I look further into carbs/sugars and fiber I will offer more information.
Robert H. Lustig, MD, UCSF Professor of Pediatrics in the Division of Endocrinology, explores the damage caused by sugary foods. He argues that fructose (too much) and fiber (not enough) appear to be cornerstones of the obesity epidemic through their effects on insulin. Series: UCSF Mini Medical School for the Public [7/2009] [Health and Medicine] [Show ID: 16717]
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