How eating too much sugar as a child impacts you for life
Kids today consume far more sugar than recommended, but the effects don’t stop in childhood. New research reveals surprising ways early sugar exposure shapes long-term health.
Parents have long known too much sugar can harm their child’s health, but a growing body of research reveals just how much damage it can do. A recent study in the journal Science found the dangers continue well into adulthood, with high blood pressure and type 2 diabetes more common in adults who were exposed to increased added sugars early in life. The results of this study and others make clear the sweet spot for sugar is well below what many kids currently consume.
While too much sugar harms adults too, it appears to be especially problematic at an age when food preferences are forming. “If you were exposed to sweet foods early in life, it’s likely that you’re going to prefer them throughout your life more than someone who was not,” says Tadeja Gracner, a scientist at the University of Southern California, who coauthored the research.
Sugar naturally occurs in some foods like fruit, but it’s also often added during processing or preparation. Children in the U.S. certainly eat plenty of added sugar, consuming an average of 17 teaspoons of this a day (almost 300 calories).
This is well above the 10 percent of calories in added sugars recommended by dietary officials for children over age two, and far from the ideal of less than five percent of total calories the World Health Organization suggests. Ten percent translates to roughly 100 to 200 calories, depending on the age of the child. Children under two should eat no added sugar.
Reducing children’s consumption is a key target in the U.S. government’s Healthy People 2030 goals. But lowering the numbers is challenging in a society where sugar is rampant—and not just in the candy aisle. Sugar appears in soft drinks, breakfast cereals, many savory-tasting processed foods and snacks, and even in baby foods. That kids and sweets are a natural combination is so widely accepted that some pediatricians’ offices give out lollipops.
“It’s not that you should never give a treat to your child,” Gracner says. But her research and others make clear that “reducing added sugar early is powerful for addressing long-term health.”
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An ideal real-world experiment
To study the impact of sugar consumption early in life, Gracner and her colleagues found a unique natural experiment. During World War II, the United Kingdom put strict limits on the amount of sugar and sweets people could purchase. These rations continued until 1953—well after health effects that might be attributable to the war had passed.
The researchers compared children born just before the end of rationing with those conceived or born soon after. Since sugar consumption doubled soon after rationing was lifted, they could confidently assume the latter group was fed a lot more sugar their first few years.
Using an extensive U.K. government health database, they then tracked the health of some 60,000 of these kids decades later. Those exposed to the rationed amount had a 35 percent lower risk of diabetes and 20 percent lower risk of hypertension as adults than those born into a world of unrestricted sugar.
These results conform with findings that conditions in utero and early in life set the stage for later health or disease.
Sugar also harms kids early on
Other research makes clear that excessive sugar consumption also affects children’s health while they are still kids.
For one thing, sugary foods are calorie dense, which contributes to the one in five U.S. children—including 13 percent of kids ages two to five—who currently have obesity, which is associated with a number of health issues.
In a scientific report released in December, a government committee charged with updating nutrition guidelines concluded that exposing children and adolescents to fewer sugar-sweetened beverages and snack foods—along with fewer salty snacks and less red and processed meats—is “associated with [a]… lower risk of obesity.”
Too much added sugar is also linked to the increased rate of type 2 diabetes in kids. This former “adult-onset disease” now affects nearly 50,000 children. Studies show that each daily eight-ounce serving of sugary beverages (including 100 percent fruit juices) consumed by boys is associated with a 34 percent increase in insulin resistance. By contrast, high insulin levels dropped after just nine days when researchers reduced sugar intake in 43 Black and Latino children with obesity to 10 percent of their diet. Those same kids also saw their liver fat significantly decrease after the reduction, which is important because this fat can impede liver function and lead to cancer and other diseases.
Other health effects of kids eating too much sugar include girls getting their first periods earlier than others and, of course, higher rates of cavities.
One thing sugar doesn’t do is make kids hyperactive—a theory that was widespread decades ago that was put to rest by research in the 1990s. But it may lead to other cognitive problems. One study in male adolescent rats found impaired attention and increased impulsivity in those who had been given a lot of fructose as babies.
Small amounts of sugar can have big effects
It doesn’t take much sugar to induce these kinds of negative health effects. When young adults consumed various amounts of sugar in sweetened beverages over two weeks, those getting 25 percent of their daily calories as added sugar saw the most increases in liver fat and blood cholesterol levels; but the problem also appeared in people consuming just 10 percent.
“I was shocked when we saw differences in [that lower] group,” says Kimber Stanhope, a nutritional biologist at the University of California, Davis, who conducted the research. Although Stanhope’s research is in adults, she believes the results would be similar for most children, except for those who are extremely physically active where the sugar could be used for energy.
The high fructose corn syrup found in most sweetened beverages and many ultra-processed foods (which combines two sugars, fructose and glucose) seems especially problematic for the liver, Stanhope says. That’s because an enzyme limits the amount of glucose that can be sent to the organ from the intestines at one time, but there’s no corresponding enzyme for fructose. When so much enters at one time, “a great deal of it ends up being stored as fat in the liver,” she says.
How to become a sugar sleuth
Reducing your child’s consumption of added sugars is tough. It starts by putting on your Sherlock Holmes hat, says Joshua Tarkoff, a pediatric endocrinologist at Nicklaus Children's Hospital in Miami, who frequently counsels parents on how to cut back. Reading labels is helpful only when you realize that sugar goes by dozens of names on product ingredient lists, including maltose, dextrose, high fructose corn syrup, and even natural fruit juice concentrate, “which can sound good even though it isn’t.”
Requiring companies to make labels clearer could help. One study found placing simple pictorial warnings on sugar sweetened beverages reduced parents’ purchases by 17 percent. But in the meantime, focusing on certain types of food could help parents navigate sugar dilemmas. Cookies and candy are obvious ones, but other foods are loaded with added sugar, too.
Encourage kids to drink more water and fewer sugar-sweetened beverages, especially since nearly two-thirds drink one or more of these beverages daily. “If they have juice with breakfast, chocolate milk with lunch, Gatorade after school, and soda with dinner, that’s hundreds of calories—and it doesn’t make them feel full,” Tarkoff says. Don’t fall for labels stating a juice drink is 100 percent natural or high in vitamin C, which research finds misleads parents into thinking the beverage is less harmful than it is.
Breakfast is also a common culprit. The packaged breakfast cereals many kids eat are actually “a semi-liquid dessert,” says Tarkoff. Opting for plain (not instant) oatmeal with fruit can cut sugar in the morning.
Snacks that kids eat throughout the day present a bigger challenge, since the majority contain high amounts of sugar. The same holds for fast foods. “Nature made sugar hard to get; man made it easy,” Tarkoff says. Processed foods may be convenient, but the more whole foods and homemade meals a child eats, the less sugar they inevitably consume.
It’s also helpful to avoid handing a child a sweetened treat to soothe tears from a fall or a fight with another child. “People can get addicted to the comfort that their favorite high-sugar food brings,” a mindset that can start in childhood, Stanhope says.
While it might be tempting to lean on artificial sweeteners, they come with their own risks. The common sweetener sucralose, for example, has been linked to obesity, as well as liver inflammation and damages to beneficial gut microbes, according to a review published in 2024.
Still, restricting added sugars entirely is not realistic. During a child’s early years parents are the nutritional gatekeepers, but that bubble bursts soon enough. “The goal is to try to teach kids boundaries—when to eat sugar and how much,” Gracner says. “The hope is then when they’re outside the house and able to eat what they want, the preferences you help set early in life will matter.”
