Timing of energy intake and BMI in children: differential impacts by age and sex

Body weight regulation may be influenced by the timing of food intake. The relationship between children’s BMI and their daily pattern of calorie consumption were investigated using data from the UK National Diet and Nutrition Survey (NDNS) 2008-2019. The sample included 6,281 children aged 4-18 years. Linear and logistic regression models investigated the timing of energy intake (103 kJ) as a predictor of BMI (kg/m2) and healthy weight status. The models showed that children aged 4-10 who consume more calories after 20:00, in comparison to less calories, had a significantly higher BMI (young girls: β= 0.159; 95% CI: 0.003, 0.315; p=0.05; young boys: β= 0.166; 95% CI: 0.028, 0.304; p=0.02). Similar findings were also present for boys aged 11-18 (β= 0.091; 95% CI: 0.003, 0.180; p=0.04), though logistic regression findings were contradictory (OR = 0.9566; 95% CI: 0.926, 0.989; p=0.009). However, older girls who consumed more calories in the morning had a significantly lower BMI (β= –0.464; 95% CI: –0.655, –0.273; p<0.001) and a lower probability of non-healthy weight (OR = 0.901; 95% CI: 0.826, 0.982; p=0.02). Physical activity reduced the likelihood of unhealthy weight status. The data suggests that food consumption later in the day in childhood and into adolescence may increase the risk of a higher BMI, especially for less active children. Developing guidance on appropriate meal timings and recommended energy distribution throughout the day could promote healthier lifestyles. Doing so may help increase parental awareness of timing of food intake and its potential impact on BMI.