Trends in energy and sugar intakes and body mass index between 1983 and 1997 among children in Great Britain

Background: It has been suggested that rising obesity among children is partly attributable to sugary foods and soft drinks driving an increase in energy intake (EI). Yet historical data on sugar intake are sparse. The present study calculated total sugar intake de novo among 3296 children aged 10-11 and 14-15 years in 1983 and compared EI, macronutrients and sugar sources with data from 459 children of same age in the 1997 National Diet and Nutrition Survey. Methods: Secondary analysis of 7-day weighed diet records and anthropometric data from two British surveys. Compositional data on sugars applied to individual food codes to calculate sugar intake and sources for 1983. Trends examined before/after adjustment for low/high energy reporting (LHER) defined as EI : basal metabolic rate < 1.16 or > 2.65. Results: Mean EI (kJ day-1) was 7% lower in 1997 than in 1983, mainly as a result of lower fat intake. After excluding LHER, mean EI was 3% lower in 1997. Mean body mass index (BMI) increased by 0.7-1 kg m-2 (2-3 kg). Total sugar intake averaged 115 g day-1 in 1983 and 113 g day-1 in 1997 (122 versus 127 g day-1 excluding LHER, P = 0.08). Excluding LHER, fat energy was lower in 1997 (35.4% versus 37.8%) and sugars slightly higher (23.6% versus 22.3%). Sugar sources showed a marked shift away from table sugar with smaller falls in milk, biscuits and cakes, counterbalanced by an significant increase in sugar from soft drinks and, to a lesser extent, fruit juice and breakfast cereals. Conclusions: Althugh the study design precludes drawing causal inferences regarding nutrient intake and obesity, a higher prevalence of under-reporting and lower levels of physical activity in 1997 could explain the paradox of lower reported EI and rising BMI.