Prospective association between later eating and obesity in school-age children from the China Health and Nutrition Survey (CHNS)

Purpose: Eating later in the day (dinner and evening snacks) may have a role in the development of obesity. However, most studies are cross-sectional and rarely focus on children in Eastern countries. Therefore, we investigated associations between dinner/evening snacks intake and later obesity in a nationally representative Chinese sample.

Methods: A total of 1292 children participating in the ongoing open cohort (CHNS) from 1997 to 2011, with complete 24-hour dietary recall for three consecutive days at 7-8 years and anthropometric data over 2-4 years of follow-up, were included. Dietary recalls recorded food names and size (grams) for each meal or snack consumed. Chinese food composition tables were used to capture energy intake (kcal). “Dinner/evening snack size” was the percentage of total energy intake (%TEI) for dinner or evening snack. “Dinner/evening snack frequency” was the total number of dinners or evening snack over 3 days (0-3 dinners, 0-3 evening snacks). Outcomes (body mass index (BMI); overweight/obesity) were assessed at 10.5 years. Multiple linear and logistic regression was used for estimating the association between later eating and each outcome. Interaction analysis was used to assess gender differences. Adjustment was made for age, gender, residency, parental education, maternal age, physical activity, maternal BMI, snack frequency, TEI and baseline BMI.

Results: Children had 36.0% (SD 9.4%) and 2.1% (SD 5.8%) of TEI for dinner and evening snacks respectively. Average dinner frequency was 3.0 (SD 0.2) times over 3 days, and 98% of children ate dinner every day; average evening snack frequency was 0.3 (SD 0.8) times over 3 days, only 6% of children ate evening snacks on all 3 days, 10% ate them once or twice, and 84% did not have any. Having evening snacks was associated with higher outcomes (BMI: b (95%CI) =0.50 (0.18 0.83) kg/m2 per time/3 days; overweight/obesity: OR (95%CI) =1.74 (1.19 2.55) per time/3 days). No other associations or interactions were found.

Conclusions: We observed that consuming evening snacks, but not dinner, were prospectively associated with obesity. Therefore, it is worth considering later eating behaviours in preventing obesity in children in Eastern countries.