How much sugar is too much? UAB neuroscientists weigh in

Eating foods that contain sugar in regulated amounts may not be exceedingly harmful, but overconsumption of sugar can lead to a significant impact on brain function and overall mood. The fall and winter months are an exciting season as people of all ages celebrate many holidays. Throughout this time of year, sugary foods are prominent at parties or while trick-or-treating. This often leads to the question “how much sugar is too much?” 

Experts from the University of Alabama at Birmingham advise that eating foods that contain sugar in regulated amounts may not be exceedingly harmful. However, overconsumption of sugar can lead to a significant impact on brain function and overall mood, and UAB experts recommend ways to enjoy sugary treats mindfully.

The influence of sugar on the mind and body

The consumption of sugar can influence our minds and bodies in many ways. To understand this influence, it is important to recognize that there are two types of sugar: refined sugar, found in sugary treats or other foods like sauces or breads, and fructose-glucose, healthier sugar found in fruits and vegetables.

J. Andrew Hardaway, Ph.D., assistant professor in the UAB Department of Psychiatry and Behavioral Neurobiology, says it is well established that the consumption of food in general, and sugar in particular, results in increased dopamine levels in the striatum — a part of the brain that is involved in decision-making, motor control, emotion, habits and rewards. He also mentions that this contributes to the short-term positive mood-altering aspects of sugar intake.

So why does sugar impact minds in this way? According to Sofia Beas Ph.D., assistant professor in the UAB Department of Neurobiology, sugar can impact brain function because of its influence on glucose levels — a type of sugar that serves as the brain’s main source of energy.

As we consume sugar, glucose enters our bloodstream, causing cells to extract the glucose to use it for fuel and energy. The sugar found in candy bars or other sugary foods are a type of sugar called refined sugar. This type of sugar is densely packed, lacks any type of nutrient and is absorbed quickly by the body.

Beas says this results in blood sugar levels spiking and then dropping quickly, leading to hypoglycemia — often referred to as a “sugar crash.” This can cause fatigue, irritability, anxiety or mood swings.

The effects on mental health

While there is no direct link between high sugar intake and mental health, it is clear that conditions like anxiety and depression are more common in people who have a high body mass index and consume high amounts of sugar. 

“The causal relationship between anxiety, depression, and BMI and obesity isn’t as clear in people,” Hardaway said. “But in model systems, long-term access to sugar-rich obesogenic diets can produce anxiety and depressive-like phenotypes and behaviors.”

Likewise, Beas explained that “excessive sugar consumption over time can lead to problems like insulin resistance, which is linked to cognitive decline and an increased risk of Alzheimer’s disease.”  

Because of sugar’s addictive-like responses in the brain, Beas states, the repeated consumption can lead to cravings and overconsumption. This can result in a cycle of mood changes dependent on sugar intake.

The good side of sugar

Understanding that not all sugars are bad is an important fact to maintain a healthy diet.

Sugar can be found in many naturally grown foods, such as fruit and vegetables. These types of sugars are referred to as fructose and glucose, and contain vitamins, fiber and other nutrients.

“Our bodies take longer to digest these types of sugars, so they do not tend to produce spikes in our blood sugar and insulin,” Beas said.

Beas explains that sugar in moderation, such as during holidays or special occasions, does not tend to cause long-term consequences. This is especially important to those who have children, as forbidding foods or labeling them as bad can cause more harm than good.

“We need to be careful to stigmatize any type of food by making it ‘forbidden,’” Hardaway said. “Food is needed to provide fuel for growing bodies and brains. Stigmatizing food and/or perseveration on children’s body sizes and shapes can increase the risk for later eating disorders.”

Beas suggests a technique that can be useful during the festivities this season. She shares that she asks her children to choose a few pieces of candy and save the rest for another time. Then, she saves a few pieces and gives the rest away. She notes that this is not a strategy that all people can use, but she encourages everyone to tackle it as a community.

Tips to enjoy sugary treats this holiday season

This holiday season, one can still enjoy sugary foods while being mindful about its effect on the brain. Here are some ways to safely celebrate this holiday season: 

• Consider offering treats that do not contain “added sugars” while trick-or-treating, such as pretzel bags or even non-food options.
• Encourage children to listen to their body’s signals to know when to stop eating sugar, as it affects blood sugar regulation. Studies indicate children can self-regulate their sugar intake.
• Store candy in a less-accessible location as this can help decrease the overconsumption of sugar.
• Do not stigmatize foods. Both experts express the importance of this tip as it can do more harm than good. Stigmatizing foods can increase the risk for eating disorders.
• Substitute natural options such as fruits and vegetables for sugary foods.
• Enjoying sugary foods during holidays or special occasions does not lead to long-term consequences. It is all about moderation.

Click here to read more tips for healthy living during the holidays.