Characteristics of self-selected portion size in young adults.
OBJECTIVE
Individuals' perceptions of portion size have not been examined with respect to body mass index (BMI; calculated as kg/m(2)), food form, food macronutrient, or food-energy density. The primary objective of this investigation was to evaluate the characteristics surrounding college students' perception of typical portions of real food items.


METHODS
This study was designed as a quasi-experiment with independent repeated measures of food form (amorphous, solid, liquid), food macronutrient content (low carbohydrate, high carbohydrate, low fat, high fat), and food-energy density (low, high), as well as one independent subject variable of sex (male, female). The main dependent measure was self-selected portion size representing what each participant felt was their typical portion of 15 food/beverage items. In addition, BMI was treated as a continuous predictor variable in regressions for portion-size estimation.


RESULTS
Participants (n=51) chose substantially larger portion sizes as compared to reference portion sizes in 10 of the 15 food/beverage items. When accounting for intervening variables, BMI positively predicted self-selected portion size for six of 15 food/beverage items (R(2)=0.29 to 0.38). In addition, participants chose significantly larger portion sizes for high-carbohydrate foods when compared to high-fat foods (191.65 vs 145.40 g; P=0.004).


CONCLUSIONS
A strong relationship between BMI and large portion sizes for high-energy-density foods, snacks, and high-carbohydrate foods was found. In addition, participants selected much smaller portion sizes for high-fat foods items relative to high-carbohydrate foods.
Burger
Kyle S
KS
Department of Food Science and Human Nutrition, 1571 Campus Delivery, Colorado State University, Fort Collins, CO 80523-1571, USA. kyle.burger@colostate.edu
Kern
Mark
M
Coleman
Karen J
KJ
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D004034:Diet Surveys; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000032:analysis; D004041:Dietary Fats / Q000008:administration & dosage / Q000032:analysis; D004435:Eating / Q000523:psychology*; D002149:Energy Intake / Q000502:physiology*; D005260:Female; D005502:Food / Q000145:classification* / Q000706:statistics & numerical data; D005504:Food Analysis; D006801:Humans; D008297:Male; D009753:Nutritive Value; D009765:Obesity / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D012737:Sex Factors; D012858:Size Perception
D004040:Dietary Carbohydrates; D004041:Dietary Fats