Fruit sugar, also known as fructose, is found in fruit and other foods. While the U.S. Department of Agriculture recommends eating a wide variety of fruits and vegetables, research shows that consuming too much fructose can lead to health conditions including obesity. If you are trying to lose weight, restricting fructose can help you win the battle.
Fructose is a sugar found in fruit, fruit juices and honey. It's the sweetest of all sugars. Fructose has the same molecular formula as glucose, another simple sugar, but they differ in structure. Both sugars are considered carbohydrates and are important in human metabolism but they are metabolized in the liver differently. While an excess of glucose is shuttled out of the body by insulin, too much fructose is stored as fat. Some people may have a hereditary fructose intolerance.
Foods high in fructose include sodas, apples and applesauce, honey, pears, agave, fruit juices like apple and grape juice, grapes, dates, watermelon and mangos. Many processed, packaged foods -- like cereal and energy bars -- also contain high amounts of fructose due to the addition of high fructose corn syrup, a processed sugar containing 55 percent fructose. Fruits with the lowest amounts of fructose include cranberries, nectarines, apricots and clementines.
To lose a pound of fat, you must burn 3,500 more calories than you take in. In order to do that, many people either cut back on the number of calories eaten each day or increase their exercise to burn off more calories. Eating foods high in fructose, however, can subvert your attempts to lose weight because fructose is metabolized in the body differently than other sugars. A 2010 study conducted by researchers at Princeton University found that rats given high amounts of fructose had an increase in weight, body fat and triglyceride levels over rats fed the same amount of calories without the added fructose. The researchers concluded that high amounts of fructose can contribute to obesity. While eating fruit is still a good idea for overall nutrition, consuming foods with less fructose and more fiber can help increase weight loss.
While some fructose is beneficial, too much fructose can lead to conditions such as gout, obesity, metabolic syndrome, cardiovascular disease and kidney failure. Even more importantly, a 2010 study published in “Cancer Research” found that fructose actually feeds and helps replicate pancreatic cancer cells. The researchers surmise that reducing fructose intake may be able to slow the growth of certain cancers.
- FitSugar.com: Too Much Fruit Sugar
- DrKaslow.com: Fruit Sugar
- Georgia State University: Comparison of Glucose and Fructose
- "American Journal of Physiology"; Fructose, but not Dextrose, Accelerates the Progression of Chronic Kidney Disease; Michael S. Gersch, et al; 2007
- Princeton University: "A Sweet Problem: Princeton Researchers Find Fructose ..."; March 2010