Fast Food Fallacy: Diet and Cost

Abstract & Commentary

By Russell H. Greenfield, MD, Editor

Synopsis: Using a unique model based on a single parent raising one child, researchers showed that following a carefully chosen whole foods diet is less expensive than a convenience/fast food diet. Unfortunately, for people without means, even a healthy diet cannot be sustainably pursued without financial support.

Source: McDermott AJ, Stephens MB. Cost of eating: Whole foods versus convenience foods in a low-income model. Fam Med 2010;42:280-284.

The authors of this trial sought to determine whether a whole food (healthy) diet was economically feasible when compared to a fast-food (convenience) diet in the absence of federal or state assistance. They created a model based on a single parent raising one child in an urban environment, with Baltimore City chosen as the area representative of at-risk urban populations (median annual income derived from the 2004 census, $29,792). Mean living expenses included rent and utilities, transportation costs, clothing, school supplies, taxes, and anticipated food consumption. Additional food items, entertainment, costs, credit card debt, and health care costs not covered by employers were not included in the analysis. Estimates for child food costs were taken from the U.S. Department of Agriculture (USDA) Cost Calculator. Costs were calculated for age 1-17 for a single parent household with income less than $58,670, the lowest available income option.

Daily food intake was derived from recommendations from the American Heart Association and the American Academy of Pediatrics, and costs associated with a whole foods diet were presented as retail averages from three large supermarket chains in Baltimore, with the least expensive options used in each food group (generic, frozen, bulk, and canned products). Convenience diet costs were taken directly from a large, multinational fast-food chain. Breakfast meals included a sandwich, hash-brown potatoes, and coffee or juice. Lunch and dinner meals included a sandwich, medium-sized fries, and a 21-ounce carbonated beverage. A representative children's meal included a sandwich or chicken-based bite-sized nuggets, small French fries, and a small carbonated beverage.

The number of calories per ounce of food and cost per calorie were computed for the average healthy diet. Caloric values for fast food items were obtained using on-line nutritional information and cost per calorie computed. Only adult diets were considered in this part of the analysis.

Annual food costs associated with the healthy diet model were $5,019. Average child food costs were estimated to be about $191 per month, or approximately $2,290 annually. Based on an average daily intake of 1,800 calories as recommended by the USDA, annual estimated food costs for an 18- to 35-year-old adult was $2,730 (about $227 per month). Notably, dairy products comprised the largest percentage (> 35%) of adult food costs. Vegetables and the combination of fruits and lean meats each accounted for about one-fourth of food costs. The model based on convenience/fast food estimated annual expenditures on food to be $10,298. The estimated adult monthly convenience diet expense was $465.

Cost-per-calorie values for the healthy and convenience diets were $0.0042 and $0.0055, respectively.

Using this study's model, housing costs represented 68% and transportation costs 23% of available income, while food products from a healthy or convenience diet would represent 18% of total income (in line with USDA estimates) and 37% of available income, respectively. Thus, annual expenditures associated with either diet contribute to a negative annual household budget. The authors conclude that it is difficult for families living in low socioeconomic (SES) communities to meet recommended dietary guidelines without income assistance, although a carefully chosen healthy diet is more cost-effective.


We have largely taken as gospel the idea that people living in lower SES areas will eat proportionately more fast food than higher income individuals because: 1) there is an increased density of fast-food establishments in low SES communities, and 2) fast food is cheaper. The present study calls the validity of the latter assumption into question (there's no arguing assumption #1, however).

The focus of the study analysis was on cost per calorie, which, while inadequate for the purposes of quantifying costs associated with optimal nutrient intake, can be taken as a marker of the quality of food being purchased. Most everyone accepts that a diet high in convenience foods is associated with higher rates of obesity (including childhood forms), cardiovascular disease, and diabetes. Fast-food meals typically represent high-calorie, high-fat options that are deficient in vegetables. Fast-food restaurants are concentrated in low SES neighborhoods, and the availability of fresh produce is notoriously poor in these same areas. Buying frozen vegetables or in bulk saves money but, at least in this model, not enough. As the authors state, "Especially in difficult economic times, it is unclear how many Americans can actually afford to 'eat right.'"

The model is not completely accurate, of course, as costs associated with time needed for shopping and food preparation were not factored in, nor was variability of the menu, but these concerns pale in importance in comparison to the authors' conclusions. On the upside, the idea that eating healthily with a focus on reasonably priced produce is more affordable than fast food is a potential game-changer. One problem is that little will change until good supermarkets selling healthy fare establish themselves in low SES areas. The larger problem, however, is that even were such markets to open in low SES communities, the financial pressures of meeting basic dietary guidelines are still excessive for too many people. Until government subsidies are put in place for healthy food, rates of obesity and malnourishment will continue to climb in this country.