Background – The prevalence of obesity and type 2 diabetes have increased over the last 20 years while mortality from coronary heart disease has been declining. The reasons for these changes remain relatively unclear as longitudinal data on predictors of obesity change are scarce.
Objective – To understand the food and lifestyle antecedents of BMI and their changes over time between 1976 and 2005.
Design – 300 to 725 self-reported questionnaires from the Sydney Adventist Hospital were randomly selected for the years 1976, 1986 and 2005. Analyses included simple descriptive statistics, reliability analysis, univariate analysis of variance and linear regression analysis.
Outcomes – In 1976 dieting, physical activity, breakfast, chicken and pie/cake consumption predicted BMI for males; for females dieting, time urgency, eating between meals, butter and soft drink consumption were predictive. In 1986, dieting, physical activity, eating between meals, regular meal patterns and consumption of spreads, coffee, cereals, and salt predicted BMI in males; dieting and consumption of margarine, spreads and coffee were predictive for females. In 2005, choosing low-fat foods, consumption of eggs, spreads, coffee, cola and liquor predicted BMI for males; consumption of cola was predictive for females.
Conclusions – Foods and behaviours appear to be differentially related to BMI by sex and year. Factors predicting increases in BMI reflected changes in food patterns toward more energy dense foods.