Rethinking Dietary Guidelines

Many public health recommendations are not truly evidence based (Brownson et al., 2003). Although some public health decisions can and should be made in the face of inconclusive data, many should not. The need for restraint may be especially salient when considering dietary guidelines. Dietary fat recommendations are a case in point, because they may have led to significant and harmful unintended consequences. By a congressional mandate, the US Department of Agriculture (USDA) and US Department of Health and Human Services (US DHHS) issue revised dietary guidelines every five years. The 1980 and 1985 dietary guidelines recommended the reduced intake of all fats. In 1990, a recommendation was added that <30% of total caloric intake should come from fat. This recommendation was continued in the 1995 edition, with qualifying language removed, and stated that “the Guidelines accurately reflect current knowledge” and that “the advice is scientifically sound as well as prudent and practical” (USDA, 1995). The 1995 edition began to recognize the disconnect between population-based trends in heart disease versus obesity and their relationship to fat intake: “More Americans are now eating less fat, saturated fat, and cholesterol-rich foods than in the recent past, and fewer people are dying from the most common form of heart disease. Still, many people continue to eat high-fat diets, and the number of overweight people has increased” (USDA, 1995).Then, in 2000, the Dietary Guideline Advisory Committee reversed its previous recommendation and suggested that the recommendation to lower fat intake had perhaps been ill advised, and might actually have some potential for harm: