Body Mass Index (BMI), Perceptions of Portion Size and Knowledge of Energy Intake and Expenditure

Abstract

Rates of overweight and obesity are increasing and although the causes are multifaceted, portion size has been implicated in a number of studies. The purpose of this pilot study was to investigate perceptions of portion size, knowledge of energy requirements and how these vary by Body Mass Index (BMI) and gender. Subjects (n = 216) were asked, using a 7-point scale, to rate the adequacy of a standard portion of both food and drink; select their preferred size from a choice of four different portions; asked questions related to energy intake and expenditure; and then weighed and heights measured. Results show that when presented with a choice, individuals generally prefer larger portions of food; the correlation between BMI and perceptions of portion sizes was significant; those with higher BMIs preferring larger portion; males preferring larger portions than females. In general, individuals have a poor understanding of their energy requirements and expenditure although there were no significant differences between BMI groups. Nearly half (43%) overestimated the amount of energy in a portion and most (54%) underestimated the amount of time required to burn that energy off. If the current overweight and obesity “epidemic” is to be addressed, action is required on a number of fronts; one being portion size where further research is warranted. doi:10.1300/ J385v05n02_04