Dietary restraint in relation to nutrient intake, physical activity and iron status in adolescent females.

Abstract

To investigate the prevalence of dietary restraint in a female adolescent population, and to examine the nutritional consequences of dietary restraint and its implications for iron status. A total of 64 adolescent females, aged 14-15 years, were recruited from two all-girl schools in central London. Nutrient intake, body weight, physical activity and iron status were measured. Findings were compared between three groups of subjects classified by dietary restraint. Adolescents with a higher BMI percentile were more likely to be highly restrained. Scores on the dietary restraint psychometric measures were comparable with other UK studies in this age group. Energy intake was inversely related to dietary restraint (mean energy intake (SE) for each restraint group were: low 8.99 MJ (0.48), medium 7.98 MJ (0.22) and high 7.35 MJ (0.39) P < 0.05); however, a corresponding relationship between dietary restraint and reduced micronutrient intakes was not found. Highly restrained eaters obtained more of their energy intake from bread, fruit and cheese and less from meat, meat products and confectionery. Levels of physical activity were not significantly different between the dietary restraint groups. There was a poor relationship between reported energy intake and estimated energy expenditure. Haematological parameters of iron status were similar across the restraint groups. Dietary restraint was exercised by the consumption of a "healthy eating diet". Dieting was not related to a lower iron status; however, the low dietary iron intake and poor iron status of the whole sample is of concern.