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Predictors of Dietary Behavior

Karen Glanz, Ph.D., M.P.H.
Rollins School of Public Health, Emory University

Meeting Summary
Agenda and Abstracts
Speaker Roster

The ecological model of diet, physical activity, and obesity that was developed for this workshop is a useful framework for examining what is known or believed, and to help identify research needs and leverage points for interventions to prevent weight gain or reduce obesity. Using this conceptual model, this presentation will 1) review the body of knowledge from studies presented at the workshop and reported in the literature, 2) identify questions that might be answered by further data analysis from the available studies, and 3) identify gaps in available data and related research priorities.

The following questions will be addressed for each category in the "Influences" column of the model, along with one key question related to the Eating box in the "Behaviors":

  1. What is the dependent variable or variables of interest?
  2. How is it defined, conceptualized and categorized?
  3. How is it, or can it be, measured?
  4. Has it been found to be associated with dietary behavior? How important is it?
  5. Is it changeable? Have change strategies been tested and found effective?
Clearly defined? Measures available? Associations found? Changeable? Which dietary?
Category of Influence
Biological & Demographic Yes, mostly Yes Yes


Use to target

Energy, fat, fruit/veg, etc.
Psychological Yes, for many Yes Yes, but modest Yes, in the short-term Fat, fruit/veg, eating
Social/Cultural Wide variability Yes, for some Yes, mostly for kids Some variables

Fat, fruit/veg

Organizational No, few definitions Some - schools, worksites Some; limited Yes Fat, fruit/veg
Physical Environment Limited Few Promising Yes Fruit/veg, fat, grains
Policies/Incentives Limited Some, often proprietary Yes, ecological level Yes Total food, and types

Provisional answers to these questions are summarized in the table. From this preliminary review, a few key conclusions are possible:

There is a need to clarify definitions and terminology within categories, across disciplines. For example, the emphasis on “biology” varies widely and is evolving over time – does it include race? Is it a focus on metabolism? Are their genetic/biologic factors that drive behavior? Also, the label “environment” is often used by epidemiologists to refer to lifestyle, i.e., behaviors, whereas social scientists more often use it to refer to influences outside the person. Further confusion might derive from the public health focus on “environment” in reference to physical environments and related health threats (e.g., air pollution, water quality, chemical exposures).

The further we go up the social ladder (more upstream), the less clear are the definitions, less well defined are the measures, and the more limited is the body of research. While many questions can be answered by studying mainly demographic/biological, and psychological factors, substantial unexplained variance remains. At the social/cultural level, some variables have been defined, measured, and studied; but others remain scientifically vague. There is a need to work toward better definitions and measures, and to study associations in multi-level studies (not just ecologic associations and casual observations). There has been recent progress in measuring home, school and worksite food environments, and in identifying access to foods at a general level (i.e., are there grocery stores in a neighborhoods?). However, more work is needed to see whether available data can be useful, and/or to undertake new research.

In addition to addressing the above questions, it will be important to consider applications in which predictors of both diet and physical activity are examined. Key issues include: 1) How are predictors of dietary behavior related to predictors of physical activity? and 2) How do their respective predictors operate together? Also, different research foci for different stages of the life cycle (children, adolescents, adults, older adults) are needed to assure relevant measures and research designs, and appropriate interpretation.


  1. Biener L, Glanz K, McLerran D, Sorensen G, Thompson B, Basen-Engquist K, Linnan L, Varnes J. Impact of the Working Well Trial on the worksite smoking and nutrition environment. Health Educat Behavior 1999; 86: 939-947.
  2. Booth S, Sallis J, Ritenbaugh C, Hill H, Birch L, Frank L, Glanz K, Himmelgreen D, Mudd M, Popkin B, Rickard K, St. Jeor S, Hays H. Environmental and societal factors affecting food choice and physical activity: Rationale, influences, and leverage points. Nutrition Reviews, 59, 3(II): 21-39, 2001.
  3. Fitzgibbon ML, Stolley MR. Environmental changes may be needed for prevention of overweighth in minority children. Pediatric Annals 2004; 33: 45-49.
  4. Glanz K, Hoelscher D. Increasing Fruit and Vegetable Intake by Changing Environments, Policy and Pricing: Resaurant-Based Research, Strategies, and Recommendations. In press, Preventive Medicine, 2004.
  5. Glanz K, Yaroch A. Strategies for Increasing Fruit and Vegetable Intake in Grocery Stores and Communities: Policy, Pricing, and Environmental Change. In press, Preventive Medicine, 2004.
  6. Morland K, Wing S, Roux AD, Poole C. Neighborhood characteristics associated with the location of food stores and food service places. Amer J Prev Med 2001; 22: 23-29.
  7. Story M, Neumark-Sztainer D, French S. Individual and environmental influences on adolescent eating behaviors. J Amer Dietet Assoc 2002; 102 (3 Suppl): S40-S51.
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