Effectiveness of Dietary Policies to Reduce Noncommunicable Diseases

In nearly every region, suboptimal diet is the leading risk factor for poor health; hunger and malnutrition result in substantial burdens and contribute to the incidence and prevalence of noncommunicable diseases (NCDs) (Forouzanfar and others 2015; Lim and others 2012). Improving individual and population dietary habits needs to become a health system and public health priority (IFPRI 2015). In recent years, interventions have been evaluated to improve dietary habits, including individual-level interventions in the health system (for example, nutrition counseling); population-level interventions; and novel, technology-based interventions (for example, Internet- and mobile-based programs). A detailed discussion of these interventions is beyond the scope of this chapter. Here, we focus on dietary priorities and policies for global NCDs, including key dietary targets, current distributions of consumption, and ensuing health burdens. We summarize the evidence for effective population-level interventions to improve diet quality, and we discuss data gaps and needs for assessing cost-effectiveness.

The global effects of hunger and nutrient deficiencies have been recognized for more than a century, but the emergence of poor diet as a major cause of NCDs has been documented only in recent decades (Forouzanfar and others 2015; Lim and others 2012). Optimal responses to this global challenge have been slowed by several factors, including the relatively recent attention given to the science of diet and NCDs; a historical focus on isolated nutrients rather than foods and diet patterns; and an emphasis on diet-induced obesity (WHO 2012). These factors have led to the neglect of the far larger burdens of NCDs owing to nonobesity-related pathways. Modern nutritional science, originating in the early 20th century, focused on nutrient deficiency diseases, such scurvy, pellagra, and rickets. The initial recognition in the late twentieth century of the additional major effect of diet on NCDs led to nutrient deficiency paradigms being extended to the study of chronic diseases (Mozaffarian and Ludwig 2010). Nutrient deficiency diseases, however, are explicitly caused and can be prevented or treated by single nutrients. In contrast, NCDs arise from complex perturbations of food intakes and overall dietary patterns, including insufficiencies of specific healthful foods and excesses of unhealthful foods (Afshin and others 2014; Chen and others 2013; de Munter and others 2007; Imamura and others 2015; Kaluza, Wolk, and Larsson 2012; Micha, Wallace, and Mozaffarian 2010; Mozaffarian and Rimm 2006; Mozaffarian and others 2006).

The global obesity epidemic has appropriately focused attention on diet. However, adiposity is only one pathway of effect of diet on NCDs. Diet quality has an enormous effect on NCDs, in particular, cardiovascular diseases, independent of body weight or obesity. Although undernutrition is an appropriate term for caloric and nutrient deficiency, overnutrition is an incorrect corollary for NCDs and even obesity. The term fails to capture the complexity of poor food habits that cause NCDs: (1) inadequate ingestion of healthful foods; and (2) ingestion of foods created by suboptimal processing (for example, those rich in refined grains, starches, and sugars), foods prepared by modern methods (for example, high temperature commercial cooking), and foods containing additives such as trans fats and sodium. Accordingly, the appropriate term for the global epidemic of diet-induced NCDs is not overnutrition, but malnutrition: poor dietary quality or composition.