Starting at age seven, kids can get stuck in a vicious cycle of obesity and emotional problems that is hard to escape, British researchers say.
Investigators are not sure what triggers the struggle, but new study findings suggest that, over time, youngsters who are obese are likely to develop anxiety and moodiness, while those with emotional problems are more apt to become obese.
Clear by age seven
"Awareness and understanding that higher weight and emotional problems often occur together might be important for parents," said study co-author Charlotte Hardman, a senior lecturer at the University of Liverpool in England. For health care practitioners working in prevention and early intervention, targeting both health outcomes might be of benefit".
Hardman and co-author Praveetha Patalay tracked the mental health and body mass index (BMI) of more than 17 000 British kids born between 2000 and 2002. (BMI is a measure of body fat based on height and weight.)
Although the researchers found no connection between obesity and emotional issues among very young children, the link was clear by age seven and strengthened as kids got older.
Kids who were obese at age seven had a greater risk of emotional difficulties at age 11, which then predicted a high BMI at 14, the study authors found.
"Specifically, higher body mass index and emotional problems tended to occur together in mid-childhood and adolescence, from ages seven to 14, but not in early childhood at ages three and five" Hardman said.
What's more, seven- to 14-year-old girls had, on average, higher BMI and emotional difficulties than boys.
Still, Hardman noted that boys and girls in that age range were about equally likely to struggle with some degree of obesity and/or mental health difficulties, such as being anxious or in a bad mood.
The team first reported their findings in the March 20 online issue of JAMA Psychiatry, and are scheduled to present their research this week at a meeting of the European Congress on Obesity in Glasgow, Scotland.
For the study, Hardman and Patalay analysed a nationally representative sample of kids enrolled in the UK's Millennium Cohort Study.
It collected BMI information on participants at nine months and then five more times at ages three, five, seven, 11 and 14. Their parents filled out questionnaires about their children's mental health. The findings were adjusted for factors known to affect both obesity and mental health, including gender, ethnicity, behaviour problems and parents' mental health.
Nearly 8% of the kids were clinically obese by age 14. By then, nearly twice as many were struggling with anxiety and feelings characterised as a "bad mood" the study found.
No cause and effect
Though poverty played a part in the link between weight and mental health, there was an across-the-board association between BMI and emotional problems. Hardman said that suggests social, physiological and psychological processes become increasingly important as children age.
Why? Hardman said the study didn't explore underlying reasons and it does not prove cause and effect. However, she offered a theory.
"Children with higher BMI may experience weight-related discrimination and poor self-esteem, which could contribute to increased depressive symptoms over time (as has been shown in adults), while depression may lead to obesity through increased emotional eating of high-calorie comfort foods, poor sleep patterns and lethargy" Hardman said in a meeting news release.
Samantha Heller, a senior clinical nutritionist at NYU Langone Health in New York City, reviewed the study findings.
Cycle can be interrupted
Heller said the link between obesity and mental health in children likely has many roots.
"Obese children may have less healthy diets, be less physically active, and be under the influence of the highly palatable, highly processed foods that encourage over-consumption" she explained. "Growing children, who are in the throes of discovering who they are, may be particularly vulnerable to these effects as well as being bullied, made fun of, and stigmatised by their peers".
But the cycle can be interrupted. Heller said that excessive screen time, physical inactivity and poor diet are issues that can be addressed with lifestyle changes.
"Parents and caregivers should be role models and encourage a dietary pattern of a balanced, more plant-based, less processed foods lifestyle, daily physical activity and less screen time" she said. "All of these things can help improve self-esteem and well-being, improve gut health and manage weight".
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