Age at dieting onset, body mass index, and dieting practices. A twin study

Abstract

Objective: Using a twin study design, we sought to determine whether an early age at dieting onset is a risk factor for higher adult body mass index (BMI) or use of risky dieting practices, independent of genetic and familial factors. Method: Female twins ages 18-60. years (N= 950) from the University of Washington Twin Registry completed 2 surveys an average of 3. years apart. Analyses of individual twins and within-twin pairs tested associations of self-reported age at dieting onset with (1) adult BMI at baseline, (2) change in BMI between the two surveys and (3) risky dieting behaviors at baseline. Results: In analyses mimicking studies of unrelated individuals, an earlier age at dieting onset was associated with greater adult BMI (p= 0.003), higher Restraint Scale scores (p