ing Survey of Food Intake by Individuals data from 1994 to 1998 show that fast food portions are often the largest compared to those prepared by full-service restaurants and those prepared in the home (Nielsen and Popkin, 2003). Zoumas-Morse et al. (2001) found that meals consumed at restaurants provided 55 percent more calories than meals from home. The larger portion sizes found at many restaurant/foodservice establishments combined with the sometimes higher sodium density of these foods may make meeting dietary recommendations for sodium intake a greater challenge for those consuming many meals away from home compared to those that have more control in the preparation of foods at home.
In summary, as households have changed the way they allocate their time for food preparation, and thus consume more foods away from home and from prepared grocery items, it has become more difficult for individuals to understand and control the nutrient content, including the sodium content, of their diets. The resulting implication is that changes in the food environment will be essential to allow individuals to purchase and consume lower-sodium foods.
Behavioral theories provide guidance about the determinants of a given health behavior—in this case, reducing salt intake. Understanding these determinants is useful in planning strategies to promote change. There are many theories of behavioral prediction, although there is growing consensus about a limited number of variables needed for predicting behavior change (Fishbein, 2000; Glanz et al., 2008; IOM, 2002; Petraitis et al., 1995). Three prominent theories provide important guidance on these influences: social cognitive theory (Bandura, 1994); the theory of reasoned action (Ajzen and Fishbein, 1980; Fishbein et al., 1991); and the health belief model (Rosenstock et al., 1994). The committee draws from a summary of these behavioral theories presented in a prior IOM report Speaking of Health: Assessing Health Communication Strategies for Diverse Populations (IOM, 2002), recognizing that a wide array of resources are available that apply social and behavior theories to health behavior in general and, more specifically, to nutrition (Glanz et al., 2008; IOM, 2007; Story et al., 2008). Although the synopsis provided here simplifies the health behavior change process, it is intended to apply the guidance from social and behavioral theory specifically to salt intake.
Intention to change is a major predictor of behavior change. Generally, people are able to convey the probability that they will engage in a particular behavior, such as reducing salt intake, and their own estimate of the likelihood of behavior change is generally a leading indicator of actual change. Nonetheless, people do not always behave as they intend to behave.