“Too much sugar” is the explanation parents and teachers often give when children are unruly. Bad behavior can’t be entirely blamed on sugar, but some problems such as attention deficit hyperactivity disorder (ADHD), bipolar disorder and aggressive behavior may have an evolutionary basis, showing up more often over time as people consumed more and more sugar, a new study suggests.

The amount of sugar and corn syrup that has been added to the human diet over the last several hundred years far exceeds what was ever intended for the human body.

Fructose, a component of refined sugar, along with high fructose corn syrup and uric acid, a product of fructose metabolism, may contribute to an apparent increase in behavioral disorders, University of Colorado researchers say.

Fructose lowers energy in the cells, and that triggers a food-seeking or foraging response, much like what happens when the body is in starvation mode, explained Richard Johnson, M.D., lead author of the study.

Throughout the ages, the foraging response has stimulated behaviors that help humans and animals alike secure food, behaviors that are perilous but necessary for survival. Risk taking, impulsiveness, quick decision making and aggressiveness are examples of such behaviors.

The amount of refined sugar and high fructose corn syrup that has been added to the human diet over the last several hundred years far exceeds what was ever intended for the human body. This excessive intake of sugar may overstimulate the food-seeking response and lead to impulsive behaviors ranging from ADHD to bipolar disorder to aggression.

“While the fructose pathway was meant to aid survival, fructose intake has skyrocketed during the last century and may be in overdrive due to the high amounts of sugar that are in the current Western diet,” explained Johnson, in a statement.

Parents need to start encouraging healthy eating and limiting the amount of sugar kids eat or drink pretty much from the moment a child is born.

It may be a contributor to bad behavior, but sugar is not entirely to blame. Many other factors help to shape behavior and mental health such as genetics and physical, emotional, family and environmental influences. More research needs to be done to determine sugar’s role in behavioral problems, but the possible connection between the rise in sugar consumption and the increase in diagnoses of hyperactivity and conduct disorders should not be overlooked.

Start Early
Because eating habits are formed in the preschool years, parents need to start encouraging healthy eating and limiting the amount of sugar kids eat or drink pretty much from the moment a child is born.

For starters, sugary beverages should be “off the table” because they are the worst offenders when it comes to sugar. They contain large amounts of sugar in the form of high fructose corn syrup or refined sugar. Even fruit juice needs to be given in small amounts or watered down. Teach children to enjoy water to quench their thirst and the naturally sweet taste of fresh, frozen or dried fruits to satisfy their sweet tooth.

As for adults, the American Heart Association recommends women limit their sugar intake to 25 grams per day. Men should limit theirs to 36 grams per day, about the amount of sugar in one 12-ounce can of soda.

The study is published in Evolution and Human Behavior.