Self-perception of weight status and its association with weight-related knowledge, attitudes, and behaviors among Chinese children in Guangzhou

BACKGROUND: How weight perception influences weight-related knowledge, attitudes, and behaviors in Chinese children is unknown. We investigated self-perception of body weight and its correlates, and analyzed the relationship between weight perception and weight-related knowledge, attitudes, and behaviors in children in Guangzhou, China. METHODS: We assessed self-reported weight perception, weight-related knowledge, attitudes, and behaviors in 3752 children aged 7–12 years. Underweight or overweight was defined using the Chinese criteria based on body mass index (BMI). Binary logistic regression analyses were performed to assess correlates of weight underestimation. RESULTS: In total, 27.3% of children underestimated and 6.7% overestimated their weight status. Weight underestimation was common among normal-weight (34.1%) and overweight children (25.3%). Older age, female sex, and child BMI z-score were negatively associated with normal-weight children's underestimation, whereas older age, paternal obesity, maternal obesity, and child BMI z-score were negatively associated with overweight children's underestimation. Correct answers on weight-related knowledge questions ranged from 81.5% to 98.6% and did not differ by weight perception within BMI categories. Although negative perceivers (i.e., those who perceived themselves as underweight or overweight) had a higher intention to change weight, they behaved more unhealthily on fruit intake, breakfast, screen time, and daily moderate-to-vigorous physical activities time than counterparts. CONCLUSION: Weight underestimation was prevalent in normal-weight and overweight children in Guangzhou. Negative perceivers had stronger willingness to change weight but tended to behave more unhealthily on certain behaviors than positive perceivers. Childhood obesity interventions should incorporate health education and practical support to promote healthy eating and physical activity.