Speed of eating and 3-year BMI change: a nationwide prospective study of mid-age women.

Objective: To conduct the first nationwide population survey to examine the associations between changes in speed of eating and weight gain over 3 years. The study also explored whether faster eating at baseline was related to healthy-weight women becoming overweight after 3 years.

Design: Longitudinal. At baseline, participants were randomly selected from a nationally representative sampling frame to participate in a prospective study. Women completed self-administered baseline questionnaires on demographic and health measures. Self-reported speed of eating, smoking status, physical activity, menopause status, and height and weight were collected at baseline and again 3 years later.

Setting: Nationwide study, New Zealand.

Subjects: Women (n 1601) aged 40-50 years were recruited at baseline from New Zealand electoral rolls.

Results: There was no evidence of associations between 3-year BMI adjusting for baseline BMI and either baseline speed of eating (slower and faster; P=0.524) or change in speed of eating (consistently faster eating, consistently slower eating, slower eating at baseline but not at 3 years, faster eating at baseline but not at 3 years; P=0.845). Of the 488 women with healthy BMI (18.5 to <25.0 kg/m2) at baseline, seventy-seven (15.8%) became overweight (BMI≥25.0 kg/m2) after 3 years. Compared with those who were slower eaters at baseline, faster eating at baseline did not increase the risk of becoming overweight 3 years later (P=0.958) nor did change in speed of eating (P=0.236).

Conclusions: Results suggest that once women have reached mid-life, faster eating does not predict further weight gain.