Role of Diet Quality in the Association Between Excess Weight and Psychosocial Problems in a Large Sample of Children in Spain

IMPORTANCE: The role of healthy eating in the association between excess weight and psychosocial health among children is unknown. OBJECTIVE: To investigate whether a diet based on healthy eating habits moderates the association between excess weight and psychosocial problems in a large sample of children in Spain. DESIGN, SETTING, AND PARTICIPANTS: This population-based cross-sectional study used data on a representative sample of 3772 children collected in 2017 through the Spanish National Health Survey. Statistical analysis was conducted from September 21 to October 27, 2021. MAIN OUTCOMES AND MEASURES: Body mass index was calculated as weight in kilograms divided by height in meters squared; body mass index z scores were computed following the sex and age criteria of the International Obesity Task Force and were used to determine excess weight. Diet quality was assessed using the Spanish Healthy Eating Index (S-HEI; a higher score denotes greater adherence to the guidelines of the Spanish Society of Community Nutrition and, therefore, a higher quality of diet). Psychosocial problems were assessed with the Strengths and Difficulties Questionnaire completed by parents or guardians. All analyses were adjusted for major confounders. RESULTS: Among the 3772 participants (1908 boys [50.6%]; mean [SD] age, 9.5 [3.1] years), the prevalence of excess weight (ie, overweight or obesity) was 38.4% (n = 1448). Diet quality moderated the association between excess weight and psychosocial problems (β = –0.06; 95% CI, –0.09 to –0.02). Moderation analysis revealed 2 different regions of significance according to the S-HEI score. First, the association between excess weight and psychosocial problems was greater for children with an S-HEI score lower than 67.5. Second, the association of excess weight with psychosocial problems was lower for children with an S-HEI score higher than 84.9. In addition, a neutral area was found, indicating that the association between excess weight and psychosocial problems neither increased nor decreased in those with an S-HEI score between 67.5 and 84.9. CONCLUSIONS AND RELEVANCE: The results of this study suggest that the association between excess weight and psychosocial problems is moderated by diet quality among children in Spain. These findings are clinically relevant because psychosocial problems are a major concern among children with excess weight. Because obesity is a chronic disease, it requires ongoing counseling and treatment throughout life.