Skip to main content

Verified by Psychology Today


Does Sugar Really Cause "Bad" Behavior in Children?

Does sugar really cause hyperactivity and challenging behavior?

Key points

  • Although diets high in sugar are linked to many health complications, research finds that eating sugar does not impact the behavior of children.
  • Some studies even find behavioral and academic benefits immediately after eating sugar.
  • The situations in which excess sugar may be consumed can make a child seem more hyperactive due to excitement or sensory over-stimulation.

Nearly every parent has had an experience in which their child eats more sugar than usual and seems to be bouncing off the walls or has an uncharacteristic tantrum or meltdown. We might laugh it off as a “sugar high” or even swear that they will never be allowed to eat that particular sugary food, or that quantity of it, again. This experience commonly happens at holidays, such as Halloween and Easter, when candy and sugary treats may be provided without restriction.

So does research back up this incredibly common experience? Does sugar really negatively impact children’s behavior?

Surprisingly, research consistently finds that eating sugar does not impact the behavior of children. A meta-analysis found that sugar did not seem to significantly impact the behavior, cognitive functioning, or academic performance. All studies included in this analysis compared children’s behavior, cognitive, and academic performance after eating sugar versus a placebo.

So this meta-analysis suggests that sugar does not seem to impact children on average, but are there some children who are more sensitive to sugar and thus react negatively to it?

To address this question, one study compared school-age children who were reportedly more sensitive to sugar with preschool children who were not reported to be sensitive to sugar. The researchers then asked families to implement the following diets for three weeks each:

  1. A diet high in sugar with no artificial sweeteners.
  2. A diet low in sugar but high in aspartame (an artificial sweetener which has also been suggested as a cause of hyperactivity in children).
  3. A diet low in sugar but high in saccharin (an artificial sweetener which has not been linked to hyperactivity.

Parents were told to avoid any artificial coloring, additives, and preservatives in all diets. The researchers found no differences in behavior, attention, hyperactivity, mood, executive functioning, or academic performance in either typical preschool children or the sugar-sensitive children on any of the three diets. In fact, the researchers tested 39 different variables and found no difference among the diets on any of these variables.

Some studies even find behavioral and academic benefits immediately after eating sugar. One study found that children who drank a high-sugar beverage showed improved memory and classroom performance when compared to children who drank a sugar-free drink. Another study examined the impacts of sugar on the behavior of juvenile delinquents. The researchers found that adolescents who ate a high-sugar breakfast, particularly those with teacher-reported hyperactivity, showed improved behavior on some measures when compared to children who ate a sugar-free breakfast. Finally, research also found that children who ate a high-sugar snack showed improved memory compared to children who ate an artificially sweetened placebo. Researchers speculate that the brains of children may require more glucose to operate efficiently. Glucose is what your body breaks down sugary foods into and it's the brain's primary source of energy, thus explaining why behavior and academic performance may be improved after consuming sugar.

Critics of the studies described above may argue that these experiments do not represent how sugar is consumed in “real life” and that following children for three weeks is too short of a time period to see significant results. Another limitation of these experiments is that they compare the impact of sugar to a placebo which is most often an artificial sweetener such as aspartame or saccharin. They use artificial sweeteners because it is essential that the placebo taste sweet so that the research participants’ own expectations don’t impact the results. But it remains unclear the impact that these artificial sweeteners may have on behavior.

Addressing some of these concerns, another study examined links between sugar consumption in children 8-to-12 years old as reported by children from their daily lives and behavior and sleep. The researchers found that 81% of the children in this study exceeded the recommended sugar intake (with the average child consuming the amount of sugar in 22 Oreo cookies per day!). Yet, sugar consumption was not correlated with any behavioral or sleep measures. It is important to note that this study is correlational, meaning that this cannot be interpreted as evidence that sugar does not cause behavioral and sleep problems.

How can this be true?

The research on sugar and behavior is limited but consistently shows that sugar is not linked to behavior in children. Still, you may be thinking of a specific instance of a “sugar high” that undoubtedly caused hyperactivity and challenging behavior and wondering how nearly every parent has experienced this phenomenon if sugar really has no impact on behavior. One reason could be parental expectation. Research finds that when children are given a placebo and their parents are told it is a high dose of sugar, parents report their children to be significantly more hyperactive. Social reinforcement may encourage these expectations. For example, when a parent says, “It seems like he is on a sugar high,” other adults around them are likely to back up this observation (“Of course; that happens to every child on Halloween”).

In addition, the situations in which children typically consume a lot of sugar (such as holidays and birthday parties) may make a child seem more hyperactive due to excitement or sensory over-stimulation. In other words, it may be the situation and not the sugar that causes the behavior.

The Health Impacts of Sugar

It is important to mention that a diet high in sugar is known to have a negative impact on children’s health. Research finds that a diet high in sugar is associated with an increased risk for obesity, cardiovascular disease, type 2 diabetes, and dental cavities. So, how can you handle sugar with your kids?

Sugar is a complicated topic and you have to make the best decision for your child and family. Your child may have health issues that make it particularly important to avoid sugar or you may believe that the health risks are so serious that it makes sense to avoid sugar entirely. You may also strongly believe that your child responds negatively to sugar and that the research described above doesn’t necessarily prove you wrong. (Research typically only shows what is true for most children, not all children.) However, if you want to provide sugar for your child in moderation, the following tips may be helpful:

  1. Use “covert control” of sugar rather than restriction to help your child learn to eat sugar in moderation. Research suggests that parents should avoid restricting all sugary foods from a child’s diet. Research finds that, when parents restrict sugary foods, their children might eat less in the short-term but become more preoccupied with the food over time. Another study found that when parents restricted food, children show excessive eating of these restricted foods when given access to them. So how do we avoid restricting intake of sugar without our child eating a package of Oreos between every meal? Instead of restriction, researchers recommend that parents use “covert control” to manage their child’s sweet intake. This can include not keeping a lot of sweets around the house, avoiding eating sweets yourself in front of your children, or avoiding places that sell sweets such as candy shops. Research shows that these more subtle approaches are effective at increasing healthy eating patterns.
  2. Consider offering high-sugar foods with meals rather than as special “treats” to minimize their novelty and allure. By making foods like candy, desserts, and other treats more available as part of a meals, your child learns that they can be included in a healthy diet and should not be on a pedestal. Research finds that children actually eat less dessert when it is served with a meal than when it is served after a meal.
  3. Change your own perspective. Your own expectations may have an impact on your child. Be careful about your own reaction to your child eating sugar and your own expectations. Rather than seeing all sugar as “evil,” view it as an important energy source that is essential for your child in moderation. Research finds that when mothers who believe their children are “sugar sensitive” are told their child was given sugar (yet they were actually given a placebo), the mothers showed more controlling behavior and criticism. Because controlling behavior and criticism are associated with more challenging behavior in children, it is possible that the parents’ own expectations cause the behavior rather than the sugar itself.
  4. Try to find the cause of your child’s challenging behavior. Rather than simply blaming your child’s challenging behavior on sugar, it may be more helpful to try to find the cause of the behavior, such as attention-seeking, sensory over-stimulation, trying to escape demands, or a lack of skills such as not knowing how to ask for help.

Although diets high in sugar are linked to many health complications, there is currently no consistent evidence that diets high in sugar are linked to behavioral or academic problems. Instead of completely restricting sugar, parents may want to try using “covert control,” offering high-sugar foods with meals, changing their own expectations, and working to find the real cause of a child’s challenging behavior.

More from Cara Goodwin, Ph.D.
More from Psychology Today