While parents may believe the vitamins and antioxidants in many fruit drinks will help their children get the best start in life, a new study conducted by researchers from the University of Liverpool in England may suggest otherwise. The researchers found that many commercially sold fruit drinks and juices contain a child’s full daily recommended allotment of sugar. Although the study measured sugar that had been added to drinks, past research has suggested that even on its own, the sugar content in fruits themselves is high enough to warrant moderation.

The study, now published online in the British Medical Journal, assessed the sugar content of 203 standard portion sizes (200 ml) of fruit juices, 100% natural juices, and smoothies that were specifically marketed to children. The team did not measure the sugar found in the original fruit, but rather the amounts that had been added to juices as sweeteners during manufacturing, usually in the form of honey and syrups. These sugars are metabolized differently within the body than those found in fruit’s natural form.

Although sugar found in fruit is chemically the same as that found in refined sugars, such as sweeteners, the additional fiber found in fruit stops these sugars from being broken down too quickly. Refined sugars have been processed so much that they are broken down in the body quickly. This leads to an immediate energy boost, which, if not burned off quickly, can result in weight gain. Results revealed that as many as half of the products assessed contained at least a child’s entire daily recommended maximum sugar intake of five teaspoons (19g), Medical Xpress reported.

Study author Simon Capewell told Medical Xpress that, although parents may genuinely work to control their children’s sugar intake, the high sugar content in these drinks can make this difficult. In addition, the study found that many products contain a reference table for sugar intake designed for the nutritional needs of an average-sized active adult women, not a child.

“The sugar content of the fruit drinks, including natural fruit juices and smoothies tested, is unacceptably high,” said Capewell. “And smoothies are among the worst offenders."

While the study looked specifically at the added sugar content in fruit drinks, many do not realize just how much sugar many fruits have before anything extra is ever added to them.

“Fruit is high in a sugar known as fructose. Even though the sugar is coming from this healthy source, you still have to use moderation,” Brigitte Zeitlin, a dietitian at B-Nutritious, told U.S. News Health.

For example, two average-sized apples have about the same amount of sugar as one 16-oz bottle of Coke, Authority Nutrition reported. Thankfully, fruits are also high in fiber, which means that when you eat a whole fruit you spend so much energy digesting it, the sugar content doesn't have a chance to cause any real harm. However, juicers take all this valuable fiber out of your food and leave high sugar content behind.

“The major thing you miss out on when you juice your fruits is the fiber,” Lisa Moskovitz, a dietitian at NY Nutrition Group who was not involved with the study, told Medical Daily. “Fiber helps with satiety, fullness, and blood sugar control so your kids aren't bouncing off the walls immediately after ingesting.”

Without fiber too much sugar can enter the bloodstream at once. Too much sugar in the body without an effective way to burn it off, no matter where it originated from, can put you at risk for developing diabetes and cause unhealthy weight gain.

“While this may be a new study, and new information to some, fruit juice has long been known as a major, and unnecessary source of sugar in children's diets,” explained Moskovitz. “In some cases fruit juices can have as much sugar per ounce as in soft drinks. “

Capewell hopes that his findings may lead to certain changes in the regulation of fruit juices in the United Kingdom and elsewhere, so as to better protect children’s health. For now, Moskovitz suggests giving kids whole fruits to snack on, but avoid fruit juices.

“If your children really insist, limit to 4 oz per day and dilute it with plain water to minimize the sugar content yet still make everyone happy,” Moskovitz concluded.

Source: Bouton J, Capewell S, Hashem KM, et al. How much sugar is hidden in drinks marketed to children? A survey of fruit juices, juice drinks and smoothie. BMJ . 2016