lower resting heart rate (a measure of cardiorespiratory fitness), lower blood pressure, and lower body mass index levels (Taylor et al., 1991; Farquhar et al., 1990) in the intervention communities. The Stanford and Minnesota projects included change in diet among their objectives, but these studies did not report notable successes in affecting dietary fat or dietary cholesterol, although an effect on plasma cholesterol was reported in the Stanford Five-City Project (Farquhar et al., 1990).
There were also a small number of evaluated mass-media interventions focused on diet. These included the “1% or Less” campaign in Wheeling, West Virginia, which showed that more adults in the state switched to low-fat milk than in a control community after a campaign in 1996 (Reger et al., 1999); and the Victoria, Australia’s “2 Fruit ‘n’ 5 Veg Every Day” campaign that ran from 1992 to 1995, which showed some increase in reported consumption of these targeted foods (Dixon et al., 1998).
The National Cancer Institute-sponsored “5 A Day for Better Health” program, for which mass-media promotion of fruit and vegetable consumption was a component, showed varying degrees of success. California data for the initial “5 A Day for Better Health” program from 1989 to 1991, as well as the subsequent national program, revealed small increases in consumption of daily servings of fruit and vegetables, though evaluators suggested that these may well have reflected ongoing secular trends (Foerster et al., 1995) or demographic shifts (Stables et al., 2002).
The findings on diet interventions, like those regarding physical activity, clearly were mixed. The 5-A-Day evaluations represented efforts of a different magnitude than any of the described physical activity interventions, yet there were no clear associations between those efforts and dietary changes. These results are of concern when considering large-scale dietary interventions. At the same time, it is evident that substantial changes in the U.S. adult diet have occurred during the last few decades, most strikingly in the reduction of dietary cholesterol and resulting levels of plasma cholesterol (Frank et al., 1993). Although evaluations of deliberate campaigns may not show consistent evidence of influence on dietary intake and outcomes, there are some influences producing large shifts in dietary knowledge and behavior. The idea that such shifts reflect general media coverage of dietary issues, creating in turn a substantial demand for low-cholesterol, low-fat products, and more recently, low-carbohydrate products, is worth serious consideration.
Approaches that seek to affect the shape of media coverage of diet and/ or physical activity might merit high priority. One of the most difficult barriers to successful public education programs is achieving high rates of exposure to persuasive messages. Even if a carefully mounted intensive education effort was effective for the audience it could reach, it may not be feasible to reach large audiences with those messages. Resources may not be