Package unit size and amount of food: do both influence intake?
OBJECTIVE
Large portions increase intake and are hypothesized to contribute to the obesity epidemic. However, it is unclear if portion size affects intake through changes in the unit size of available food or the overall amount of food available for consumption. Thus, this study examined the independent effects of package unit size and amount of food on intake. It was hypothesized that both variables would influence intake.


METHODS
Non-obese (BMI <30 kg/m(2)), non-smoking, unrestrained, college-aged men (n = 12) and women (n = 16) who regularly consumed (>or=3 times/wk) snack foods were randomly assigned to one of four groups crossing package unit size (small vs. large) and amount of food (small vs. large). Participants were given a box with 4 snack foods (potato chips, cheese crackers, cookies, and candy) packaged according to their assigned group to take home and eat over 3 days. Dependent variables were energy and gram intake of provided snack foods.


RESULTS
An effect of amount of food was found (p < 0.01). A 100% increase in the amount of food provided produced an 81% increase in energy consumed from the snack foods [small amount, 21,037.6 +/- 10,852 kJ (5,028 +/- 2,596 kcal) vs. large amount, 11,640.7 +/- 4,914.1 kJ (2,782 +/- 1,174 kcal)]. No effect of package unit size was found.


CONCLUSIONS
These results suggest that the amount of food available to eat strongly influences intake.
Raynor
Hollie A
HA
Department of Nutrition, The University of Tennessee, 1215 W. Cumberland Avenue, Jessie Harris Building, Room 229, Knoxville, TN 37996, USA. hraynor@lifespan.org
Wing
Rena R
RR
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D004032:Diet; D004435:Eating; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005502:Food; D018857:Food Packaging / Q000379:methods*; D005518:Food Preferences; D006801:Humans; D008297:Male; D014894:Weights and Measures