• Researchers say MRIs have revealed signs of brain damage in teens with obesity.
• They say the damage may affect a hormone in the brain that signals to people when they’re full and should stop eating.
• Experts say it’s important to treat obesity in teenagers because the health issues can worsen in adulthood.

A study using MRI scans has found signs of damage in the brains of teenagers with obesity.

The results of the small study were reported Sunday at the annual meeting of the Radiological Society of North America.

The research suggests that along with weight gain, obesity can trigger inflammation throughout the body and the nervous system that could lead to damage in the brain.

“Brain changes found in obese adolescents related to important regions responsible for control of appetite, emotions, and cognitive functions,” Pamela Bertolazzi, study co-author and a biomedical scientist and PhD student from the University of São Paulo in Brazil, said in a press release.

Experts who spoke with Healthline note the study is small and hasn’t been published in a peer-reviewed journal.

However, Danelle M. Fisher, MD, a pediatrician and vice chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, California, says the findings could alter the approach to obesity research.

“I think this is going to take researchers in a different direction. It really would explain these patterns of behavior that we see in these teens who are having problems with obesity,” she told Healthline.

“Sometimes the eating is behavioral in nature, it’s sublimating certain emotions with food, as opposed to dealing with them in other ways,” Dr. Fisher added. “It would explain some of the rise in obesity that we’ve seen over the past many years.”

Obesity on the rise

Obesity in younger people has been on the rise over the past 50 years.

In the United States, the percentage of children and adolescents with obesity has more than tripled since the 1970s.

According to the Centers for Disease Control and PreventionTrusted Source, the prevalence of obesity in those aged 12 to 19 is now 20 percent.

It’s a problem Gina L. Posner, MD, a pediatrician at MemorialCare Orange Coast Medical Center in California, says is only getting worse.

“In my patient population, it’s really significant. We have a lot of obese teens,” she told Healthline. “We have a very sedentary lifestyle at this point. A lot of teenagers are just playing on their phone, playing on their iPad, watching TV. They’re really not getting up and out and moving as much as they used to in the past. That’s definitely creating more of a problem because we’re just a lazier culture.”

The health effects of teen obesity have posed a new set of challenges for clinicians like Dr. Posner.

“We’re seeing a lot more type 2 diabetes in younger people,” she said. “It used to be type 2 was more in obese adults and now we’re seeing it a lot in obese children as well. We’re seeing obese teenagers with diabetes, with high blood pressure, with high cholesterol. As a pediatrician, I didn’t used to have to deal with medications for high blood pressure and high cholesterol, and now I’m seeing it more and more.”

“I’m still not comfortable prescribing those medications because most of them are actually meant for people who are older and they’re not really studied well in the younger kids,” she added.

What the research showed

Researchers on the MRI study compared the brains of 59 adolescents with obesity to 61 healthy adolescents.

They found damage to the brain that was connected with inflammatory markers that included leptin, a hormone created by fat cells that helps regulate fat stores and energy levels.

In some people with obesity, the brain fails to respond to this hormone, so the person keeps eating despite having adequate or at times excessive amounts of fat stores.

“When functioning properly, leptin is a satiety hormone, meaning that our fat cells will produce leptin so that we don’t feel as hungry and eat less. In a perfect world, the more fat we have, the more leptin we would create and the less we would eat, leading us to lose weight,” Dana Hunnes, PhD, MPH, a senior dietitian at the University of California Los Angeles Medical Center, told Healthline.

“Unfortunately, however, we don’t live in a perfect world,” she added, “and according to this study, it sounds like the brain changes caused by inflammation, associated with obesity, led the brains to not properly respond to leptin and did not appropriately lower appetite.”

Bertolazzi says the researchers hope to repeat the study, after the participants have undergone a multidisciplinary treatment for weight loss, to see if the damage in the brain is reversible.

Treating obesity early

Experts agree it’s important to treat obesity in adolescence as soon as possible to limit the amount of damage done both physically and mentally to the teenager.

If left unaddressed, the effects of obesity can be significant.

“Impacts are seen physically as well as emotionally,” Sophia Yen, MD, clinical associate professor at Stanford Children’s Health’s Weight Clinic in California, told Healthline. “It can definitely impact self-esteem and cause depression. It can cause breast enlargement in boys and girls. In young women, it can cause polycystic ovary syndrome, irregular menses, hair growth, and acne. It can cause joint problems, heart problems, breathing problems, obstructive sleep apnea, liver problems, and diabetes.”

Dr. Yen says weight loss is 90 percent what you eat and 10 percent exercise. She advises that at every meal, 50 percent of the plate should include fruits and vegetables, a minimum of 25 percent should be protein, and no more than 25 percent should be carbohydrates.

Posner says it’s much easier to reverse obesity as a teenager rather than waiting until adulthood to make positive changes.

“If you’re an obese teen, the likelihood that you’re going to be an obese adult is very high, it’s hard to break that cycle,” she said.

Katie Page, MD, co-director of the Diabetes and Obesity Research Institute at the USC Keck School of Medicine, said now that researchers have established a link between obesity and brain function, efforts should turn to ways to prevent or reverse damage.

“The results from the new study are consistent with prior reports and are a major public health concern because they suggest that obesity not only increases risk of metabolic diseases, like diabetes, but it may also be linked to worse brain function,” she told Healthline.

“What we need to do now is study ways in which the damage caused by obesity could be reversed and/or prevented,” Dr. Page added. “Potential strategies could include changes in diet, increases in physical activity, reductions in sedentary behavior, and reductions in stress, all of which play an important role in brain development and cognitive function.”