Obesity in Teens Linked to Enlarged Brain Regions Associated With Memory and Emotion

Experts warn that these structural changes could have long-term implications for cognitive development.

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With more than one in three U.S. children now overweight or obese, researchers have uncovered a troubling connection: Teen obesity may be changing the size of brain regions critical for learning and emotional control, raising concerns about long-term cognitive and emotional development.

According to the authors, both decreased and increased growth can be damaging.

“This is particularly alarming, given that the teenage years are such an important time for brain development,” Augusto César F. De Moraes, assistant professor at UTHealth Houston School of Public Health and the lead study author, said in a statement.

Abdominal Fat Affected the Brain Most

The research, recently presented at the European Congress on Obesity, found that teenagers with abdominal obesity had significantly enlarged brain regions, particularly those responsible for memory, learning, and emotional regulation.

Researchers used brain scans to measure the size of several brain regions in more than 3,300 young people with an average age of 10, who were followed over four years.

The results showed that teenagers with abdominal obesity had a hippocampus approximately 6.6 percent larger and an amygdala about 4.3 percent larger than those of peers without obesity. The hippocampus helps with memory and learning, while the amygdala controls emotions such as fear, happiness, and anger.

Gillian Killiner, a specialist dietitian at 121 Dietitian, told The Epoch Times that she considers the findings “deeply concerning,” emphasizing that these brain changes raise significant worries about long-term cognitive development.

The exact mechanisms are unclear, but one possible way obesity affects the brain is through inflammation. Excess body fat sends inflammatory substances throughout the body. These chemicals can travel through the bloodstream and enter the brain. Once inside, they can trigger inflammation in brain tissue, potentially harming brain cells over time.

The relationship between obesity and amygdala volume was particularly pronounced in those with very high obesity levels, suggesting a strong link between body fat and emotional regulation, according to De Moraes. Other regions, such as the thalamus and caudate, also showed volume changes, but to a lesser extent. The thalamus acts as the brain’s central relay station, helping process and direct information to other regions. The caudate nucleus is involved in processing visual information and controlling movement.

Socioeconomic factors also emerged as a key influence on brain development.

Teenagers living in areas with limited access to quality education, safe parks, and healthy food showed less growth in key brain areas such as the hippocampus, putamen, and amygdala.

1 in 3 US Teens Will Be Obese by 2050

The research comes amid alarming trends in childhood and adolescent obesity.

The proportion of children and teens aged 5 to 19 carrying excess weight has more than doubled globally, jumping from just 8 percent in 1990 to 20 percent by 2022. This increase has affected both genders almost equally, with 19 percent of girls and 21 percent of boys now classified as overweight or obese.

Research published in December 2024 in The Lancet found that the number of obese people in the United States has increased much faster than the number of overweight people, especially among teens. From 1990 to 2021, the percentage of teens with obesity grew by about 158 percent for boys and 186 percent for girls, significantly outpacing the rise in adult obesity.

Researchers warn that if current trends continue, by 2050, nearly one in three teens and two in three adults will be obese in the United States.

Strategies for Healthier Brain Development

To support healthy brain development and reduce obesity risk in teenagers, Killiner recommended several evidence-based approaches:

• Prioritize Whole Foods: Focus on vegetables, fruits, whole grains, legumes, lean proteins, and healthy fats—especially omega-3s, which support brain health.
• Establish Regular Meal Patterns: Consistent meals throughout the day help maintain stable blood sugar levels and curb overeating.
• Reduce Ultra-Processed Foods: Limit sugary drinks, packaged snacks, and takeaway foods, which often contribute to inflammation and weight gain.
• Share Meals as a Family: Eating together encourages healthy habits and open communication.
• Build Teen Food Autonomy: Encourage teens to make food choices and learn basic cooking skills to build confidence in healthy decision-making.

Certain dietary patterns may specifically benefit adolescent cognitive and emotional health.

“The Mediterranean diet is a good option for adolescents, as it is rich in antioxidants, fiber, and unsaturated fats reducing inflammation, a key factor in both obesity and neurodevelopmental risk,” Killiner said.

She recommended a hybrid of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet: the Mediterranean-DASH Intervention for Neurodegenerative Delay diet.

“This study is a sharp reminder that adolescent obesity is not solely a weight issue, it may also influence brain structure and emotional regulation,” Killiner said. “We must act early with supportive, nonjudgmental interventions that focus on nourishment rather than restriction.”