Sociologist Pierre Bourdieu reveals in his seminal text Distinction: A Social Critique of the Judgment of Taste that lifestyle is a function of an individual's position in society. In "America's Fittest Cities," Atlantic blogger Richard Florida shows how those lifestyles are a function of uneven economic development in the US. In the rankings of the fittest Americans, "fitness" tracts roughly onto the division of labor between American cities.
Working class, poorer cities are "unfit," while wealthy cities with heavy knowledge industries are "fit." The lifestyle dubbed healthy by the CDC and others is the lifestyle most appropriate to the labor market best characterized as post-industrial, information-oriented, and "creative," while the least "fit" lifestyles are associated with heavy industry and manufacturing, remnants of an older economic paradigm.
Think of it this way: the assembly line nature of fast food is more congruent with vertically integrated heavy industry or Fordism, while farmer's markets are more in line with creative, flexible, knowledge-based industries. Foodies are more or less producing the food system of neoliberalism and flexible accumulation. In other words, the people who have the "healthiest" lifestyle are the most affluent and they use the notion of health to legitimate and generalize the culture and lifestyle associated with affluence.
Simply put, the idea of an objectively healthy lifestyle serves more to legitimate the wealthy than it does to actually address the health needs of the exploited.
As I have said in previous posts, good food is a human right, and what counts as good food or a healthy lifestyle should be determined by those living that lifestyle - not by technocrats at the Health and Human Services and the Center for Disease Control. These organizations base the assumptions of fitness for their research on the lifestyles of the elite.
For instance, the CDC's Behavioral Risk Factor Surveillance System (creepy name), on which the AFI is based, opens the exercise section with the question "During the past month, other than your regular job, did you participate in any physical activities or exercises such as running, calisthenics, golf, gardening, or walking for exercise?" So the activity of an auto mechanic or construction worker during their regular job doesn't count as exercise? Obviously, the question is remarkably biased in favor of those who do sedentary work and exercise for leisure - biased in favor of the lifestyle of the wealthy. By the very structure of the survey, a working class person cannot be as fit as an elite.
Of course, there are negative health effects to not being wealthy, such as lack of adequate food and stress, but food activists should connect these to the unevenness associated with economic development and not try to generalize one, elitist culture of health and fitness for everyone. At its root, food injustice is economic injustice. This should be the starting point.