202281 Expanding portion sizes - bigger not always better

Tuesday, November 10, 2009

Naveed Zafar Janjua, MBBS, MSc, DrPH , Epidemiology, Centers for Disease Control, British Columbia (CDC-BC), Vancouver, BC, Canada
Bushra Mahmood, MPH , Survey Research Division, Research Triangle Institute International (RTI), Durham, NC
Background: Genetic as well as environmental factors such as high consumption of energy dense diet and sedentary lifestyle have been implicated in development of obesity. Studies have indicated that it is not only the type of diet, but also the quantity of intake which is important. To date, there have been few systematic evaluations of literature on how increased potion sizes may contribute towards over-weight. This review aims at summarizing evidence on the role of expanding portion sizes on high intake of food in children as well as adults.

Methods: We searched Pubmed, governmental reports and other grey literature published during 1997 to 2008. Studies meeting methodological relevance and eligibility criteria were selected for systematic review.


During past four decades there has been an increase in portion sizes of both prepackaged and restaurant food in United States. Our current environment promotes a greater intake of energy dense food through large portion sizes. Evidence exists that increased portion sizes affect intake of food in children as young as 3 years of age. Increased portion sizes lead to a significant increase in intake of food in adults in both naturalistic as well as experimental settings.


Portion size is a modifiable environmental factor and needs to be addressed in the context of interventions directed at curbing over-weight and obesity. Public education and involvement of the food industry at the policy making level is imperative for the successful regulation of portion sizes.

Learning Objectives:
1. Demonstrate how large portion sizes of energy dense foods lead to an increased intake of food in adults as well as children as young as three years of age in both naturalistic and experimental settings. 2. Explain how forced feeding of young children may lead to a diminishing of their inherent satiety cues thereby affecting their ability to control food intake in later life. 3. Demonstrate the need for introducing regulatory measures to limit the portion sizes served in restaurants. 4. Demonstrate the need for educating the stakeholders which includes policy makers, consumers as well as food industry on the contribution of expanding portion sizes to the epidemic of over weight and obesity in the US.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am particularly interested in issues related to over-weight and obesity- especially among the minority population. As a part of my Masters project, I developed social marketing campaign for African American Adolescent girls on healthy eating. During my internship at Children's Hospital Birmingham, AL, we worked on developing an intervention aimed at eduating the providers on the assessment and treatment of child obesity. Using secondary data, I have submitted a paper on Maternal and early childhood risk factors for obesity among low income predominantly black children at age five years: A prospective cohort study - which is in review process. Also, in addition, I have attended several conferences with on health education with a focus on obesity.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.