The Fructose Factor
Yet it's possible that added sugar may have health risks even beyond what is commonly known. According to an emerging body of research, the fructose that comes from the breakdown of these sweeteners may put a unique kind of stress on the body. The reason: Fructose is processed entirely by the liver. Faced with a big load of fructose, the liver struggles to handle it and ends up converting a portion of fructose to fat molecules. Some of the fat then enters the bloodstream, where it can raise cholesterol and triglyceride levels.
Dr. Lustig says that the way fructose is metabolized by the liver -- the pathways it goes through and the enzymes it activates -- shares eerie similarities with alcohol. "A can of soda and a can of beer have the same strain on the liver," he says. "Fructose is alcohol without the buzz." Both fructose and alcohol cause the liver to trigger fat production that can boost cholesterol levels and belly fat.
And, he says, both can stimulate overconsumption. In research on monkeys, fructose didn't trigger the release of leptin -- the feel-full hormone that tells your brain that it's time to stop eating. When leptin is blocked, not only are you still hungry, you also crave more food, creating a vicious cycle.
Thankfully, the fructose found naturally in fruit (and in lesser amounts, vegetables) is not a problem. Since fruit contains fiber and is naturally filling, kids (and adults) usually don't eat it in large quantities. You'd have to eat three small apples to get the amount of fructose in a 20-ounce bottle of soda. Plus, the fiber in fruits and veggies slows digestion, so the liver doesn't get overwhelmed by a lot of fructose at once. "I'm not worried about the fructose in fruit," says Dr. Lustig. "Kids can eat as much fruit as they want." Fruit juice is different, though. Sure, juice has nutrients like vitamin C that soda doesn't. But that doesn't entirely make up for its fructose. A 6-ounce glass of juice every day is fine, but unlimited access isn't.
Some experts question the relevance of the research on fructose. "Many studies have used fructose in amounts much higher than people typically consume," says John White, Ph.D., a nutritional biochemist with White Technical Research who consults with the Corn Refiners Association, the trade group currently defending HFCS in a public-relations campaign. The highest consumers of fructose (18- to 22-year-olds) take in about 18 percent of calories from fructose, but researchers typically give study subjects 25 to 35 percent of their calories from fructose -- and some animal studies have used up to 60 percent. Furthermore, pure fructose is often used in studies, though in real life, people typically consume it with glucose (such as in fruits). Both factors may exaggerate the studies' outcomes, says Dr. White.
What You Can Do
"It's difficult and unnecessary to erase all added sugar from your child's diet," says Jeannie Moloo, Ph.D., R.D., a spokesperson for the Academy of Nutrition and Dietetics. Everybody's diet -- including children's -- has room for some. We asked our experts for their advice on how to cut back on the amount your child gets.
- Read the fine print.
Don't be fooled by claims on the label like "simple" and "no high-fructose corn syrup." Instead, go straight to the Nutrition Facts Panel and look for "sugar." Check to see how many grams it contains. Though the food label doesn't distinguish between added sugars and natural sugars, you can still use this rule of thumb for processed foods such as cereal, cookies, and crackers: Every 4 grams of sugar equals 1 teaspoon.
- Ban sweetened beverages.
Eliminate regular soda, fruit punch, and other sweet drinks from your fridge -- and if your child has some, consider it a sweet treat, as you would a cookie. (If your child's already getting lots of sugary drinks, artificially sweetened beverages can help cut calories and sugar. Otherwise, teaching your child to drink plain water to quench thirst is a smarter move, says Rachel Johnson, Ph.D., R.D., professor of nutrition at the University of Vermont and spokesperson for the American Heart Association, who helped create its latest guidelines for added sugar intake.) If you want to serve juice, stick to the guidelines set by the American Academy of Pediatrics: no more than 4 to 6 ounces a day for children ages 1 to 6, and no more than 8 to 12 ounces for older kids.
- Use sugar strategically.
On most days, aim to spend your child's sugar allowance on healthy foods like yogurt, whole-grain cereal, and flavored milk. "Consider the vehicle that sugar comes in," says Dr. Johnson. "I'd much rather see kids getting sugar in a whole-grain cereal than in candy or soda." You'll stretch your sugar budget further by buying plain, unsweetened versions of whole-grain cereal, oatmeal, and yogurt and sweetening them yourself with a small amount of sugar, honey, or maple syrup. Putting in just 1 teaspoon of these sweeteners will add 4 grams of added sugar, far less than manufacturers typically add.
- Rethink Dessert.
"I actually recommend having dessert every night because it brings the meal to a close and helps you feel satisfied," explains Dr. Ludwig. In his family, they splurge on something like ice cream once a week. Otherwise, dessert is usually a small square of dark chocolate, a slice of melon, or a cup of berries.
- Be Flexible.
"Totally restricting sweet treats will backfire on you because they'll become so much more desirable to your kids," points out Dr. Johnson. So it's perfectly fine to relax your rules occasionally for birthday parties, playdates, and special occasions. "What you keep in your own house and the patterns you develop as a family are what matter most," she says.