Background: Proliferation of large portions of snack and fast foods parallels dramatic increases in childhood obesity. This study investigates the prevalence, determinants, and consequences of large portions in children's diets.
Methods: As part of the 2003 Children's Lifestyle and School-performance Study, we surveyed 4,966 children in Nova Scotia regarding their usual portion sizes of french fries, meats, vegetables, and potato chips using three-dimensional graduated food models. We measured heights and weights and assessed dietary intake with the Harvard Youth Adolescent Food Frequency Questionnaire. Diet quality was summarized using the Diet Quality Index International (DQI-I). Parents were surveyed on food habits and socioeconomic background.
Statistical analysis: We used multilevel regression methods to examine determinants of children's large portion size choice and to evaluate the effect of this selection on energy intake, diet quality, and overweight.
Results: Children reported preference for portions of french fries, meats, and potato chips that are larger and vegetable portions that are smaller than what is recommended. Children from socioeconomically disadvantaged families or who frequently eat while watching television and in fast-food restaurants preferred larger portions of french fries and potato chips. Consequences of consuming large portions of these foods included poor diet quality and increased energy intake. Consuming large portions of vegetables was associated with lower energy intake and better diet quality.
Conclusions: Successful marketing of large portions of french fries and potato chips may be at the expense of diet quality and appropriate energy intake. Policy regulations and nutrition education emphasizing appropriate portion sizes provide opportunities to prevent overweight and improve future health.