Even though we know sugar isn’t great for us, there’s still something about foods sweetened with fructose—a simple sugar found in fruit, agave nectar, and honey—that suggests a vague, good-for-you aura. But once you get past the clever marketing, fructose’s wholesome reputation as a healthier natural sweetener crumbles quicker than an all-natural cookie. Whether it’s high fructose corn syrup (HFCS), table sugar (sucrose), or fruit sugar, “all caloric sweeteners are essentially the same. They’re all sweeteners because they all contain fructose,” says Robert Lustig, MD, pediatric endocrinologist at the University of California, San Francisco and author of Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease. Mounting evidence suggests eating too much fructose can wreak havoc on the body. It all starts with the liver, which is the only organ in the body that can actually process the stuff: Take in more fructose than your liver can handle, and it swiftly turns the excess into fat—a process called lipogenesis. “Every single one of your body’s 10 trillion cells can metabolize glucose, but only the liver can metabolize fructose," says Anne Alexander, the author of The Smart Diet and Editorial Director of Prevention. “Sucrose is half fructose, so it puts some burden on the liver; the glucose it contains is processed by the rest of the body. HFCS contains about 10% more fructose than sucrose, making the liver’s job that much harder. Worse, these sugars are found in foods that sound healthy.” That might explain why several studies have linked high fructose consumption to high blood pressure, high cholesterol, obesity, and insulin resistance, which can increase your risk for heart disease, stroke, cancer, and even Alzheimer’s. “When the liver’s capacity is overwhelmed, the thing that overwhelms it becomes a poison. That’s true for alcohol and other drugs, and it’s also true for sugar,” Dr. Lustig says. And like drugs or alcohol, fructose stimulates the brain’s reward center to make you feel good—for a little while, anyway. “The first time you get a hit, it feels good. But as you build up a tolerance, you have to get bigger and bigger hits to get the same effect,” Dr. Lustig says. There’s another reason why a tiny taste usually isn’t enough to satisfy us: Thanks to its insulin-spiking powers, fructose can stop the brain from producing the satiety hormone leptin, says research from the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology. In other words, even though you’ve already eaten, you still feel hungry and can’t shake the urge to scarf down more. And there is one more bit of bad news: Loading up on fructose can speed up cell damage, making you look older. In fact, fructose ages cells up seven times faster than glucose, the carbohydrate that makes up bread and pasta. Still, not all experts belong to the anti-fructose brigade. Some research, including a study published this week in the European Journal of Clinical Nutrition, says that excess calories, not sugar, are the driving force behind obesity and its suite of related diseases. Which might be a valid point—maybe we just eat too much. Except, several of the studies received funding from soda companies and other food and beverage interest groups, so it’s tough too put much faith into their findings. Which all means it might be time for us to abandon the idea that fructose, when consumed as added sugar in any type of processed food, is any better for us than refined sugar or even high fructose corn syrup. “We need to de-sweeten our lives,” says Dr. Lustig. While you don’t have to give it up completely, the 22 teaspoons of added sugar most of us eat each day is way too much. Instead, stick to the American Heart Association’s recommendation of no more than 6 teaspoons daily of added sugar for women and 9 teaspoons for men. More from Prevention: Get Sugar Smart
