Tuesday, June 02, 2009

A question (not just an answer): How much does a nutritious diet cost?

How much does a nutritious diet cost?

Some say that the high price of healthy food is making us obese and unhealthy. Others wonder how that could be so, because (even with recent inflation) food of all sorts has been comparatively cheap in the United States for many years, due to government policy and technological change in the food system.

The leading source of disagreement about the cost of an adequate diet is different definitions of "adequate," not different price estimates. Your estimate of the minimal necessary cost depends on your opinion on questions like the following:
  • whether a high level of meat and dairy is necessary for an adequate diet,
  • whether your vision of healthy food includes foods marketed as healthy (organic yogurt, low-fat cereal) or simple basic staples (whole grain rice, cabbage, carrots),
  • whether diets should be judged by their adherence to USDA's Pyramid recommendations,
  • whether diets should be judged by their adherence to the National Academies' nutrient recommendations, and
  • whether you think low-income people can cook at home, or whether instead convenience and restaurant foods are central to your definition of adequacy.
More subtly, your estimate of minimal cost depends on your opinion about whether people can change their diets in order to meet cost and nutrition goals, or whether it is inevitable that any realistic diet closely resembles the current average diet.

Reasonable answers about the cost of a nutritious diet, corresponding to different definitions of nutritious, range from even less expensive than the federal government's Thrifty Food Plan to much more expensive.

No wonder this issue generates a lot of argument! Most people on all sides of this issue leave these key assumptions implicit and unstated. Yet, these assumptions strongly influence conclusions about minimal costs.

In a recent article in the Journal of Consumer Affairs (free abstract, pay site for full article), "Using the Thrifty Food Plan to Assess the Cost of a Nutritious Diet," Joseph Llobrera and I use USDA's Thrifty Food Plan (TFP) framework to clarify the relationship between assumptions and cost estimates for nutritious diets. Let me know by email if your library does not have the journal. There is a related seminar on the Friedman School website. If you would like to play around with these models yourself, see our Thrifty Food Plan calculator. In both the seminar and the calculator, I should have emphasized more strongly that all of the dollars are in 2001 dollars per adult in the household, not adjusted for inflation (if you didn't know this, the amounts would seem unrealistically low).

For some readers, the whole computation will seem beside the point. They may reason that is clearly wrong to set the TFP cost target too low, but harmless to set it too high, so why not just pick the highest estimate? For a number of reasons, I think better food assistance policy comes from trying to choose the right estimate for a minimal cost target, rather than padding the estimate too much.

In the article, we find that the USDA's Thrifty Food Plan cost level can purchase a nutritious diet if (1) you think nutrient constraints (adequate protein, for example) are more important than food category constraints (plenty of meat), or (2) if you think it is reasonable to expect people to drastically change their current consumption pattern. If, instead, you think substantial meat and dairy amounts are essential to an adequate diet and you defer to the current consumption pattern of low-income consumers, you will probably prefer a more generous TFP cost target.

Update: Slate's Daily Bread food business blog has a thoughtful post about this article (gently needling the online presentation as "a little geeky" -- ha!).


Ed Bruske said...

Parke, there is a long history in this country of industrialists advocating a "nutritious but cheap" diet for American workers as a convenient way of telling the public that workers that a "living wage" doesn't necessarily need to be a high wage. Americans have gotten used to the idea that food should only comprise a small percentage of their income, unlike the rest of the world. Now we see an environmental movement urging consumers to avoid meat and eat more plant food, which tracks over the federal dietary recommendations and "food pyramid" founded on carbohydrates. My own feeling is that all of these pressures to eat more plant foods ignores the very serious implications of consuming large quantities of carbohydrates and the insulin response that results. To my thinking, the reason we have an "obesity epidemic," to go along with a cluster of related diseases--hypertension, diabetes, atherosclerosis--is because Americans are consuming entirely too many carbohydrates. So my idea of a health diet would call for much more consumption of healthy fats and proteins, and far less consumption of carbohydrates--basically a reversal of the food pyramid. No doubt that would be more expensive that the diet most people are used to if they are eating a lot of the cheap carbohydrates that are so abundant in our society.

Andy said...

Thank you for the fine article. I am interested in exploring the idea that healthy food is not too expensive, but rather unhealthy food is too cheap, ie it's not that milk is too expensive to be part of a healthy diet, but that coke is too cheap to resist. Would you be able to suggest a good starting point in this research?

Dave said...

Great Article

I agree with Andy here. The cheap food is delicious and so cheap that no one can resist a sneaky bite. But if done right healthy food can be cheap as well. It is alot more effort bu I suppose you are paying for quality and not quantity as the old saying goes.


Unknown said...

I think that in addition to economics, access is another important component to consider. The government managed to get foodstamps in a debet card format yet you still can not use your food stamps for a community supported agriculture share or to have Safeway deliver groceries to your home. Generally speaking, people using food stamps have less transportation option, and hence less access to affordable healthy food. It's an interesting discussion with very real implications. I look forward to reading more perspectives on the topic.

Badger said...

@Ed: those epidemics have little to do with the consumption of carbohydrates. My diet is 50% carbs, 40% fruits, nuts, and veggies, and 10% meats, and I have none of the health issues listed - and issues I have had have been alleviated since adopting a workout routine. It comes down to one thing - if you consume calories over your basal metabolism, you gain weight. Weight gain, when in excess, forces your body to work harder to function for the greater mass. This high carb diet is no different from the Italian diets in the Tuscan, northern Italy region. They don't have severe problems there with obesity, diabetes, etc. Please find evidence to support the claim that breads and pastas when consumed to match metabolic rate that increases hypertension and atherosclerosis.

I think we have to stop looking at food that is "healthy" and "unhealthy." People need to find food that is simple, good, and fresh. I made a meal the other day for $6.00. It was enough to feed me for 3 LARGE meals and took only 30 minutes to make.

I eat over 3500 calories a day so I eat a lot and need many cheap options!

Ash said...

While I think Parke’s article is fascinating and very useful for thinking about healthy and affordable diets, I am particularly interested by the comments that this posting received. The discussion over a healthy high or low carbohydrate diet reinforces Parke’s argument that in order to discuss health and affordability, we need to examine our assumptions about what is healthy in the first place. We must all consider how we understand a “nutritious diet” and what parts of that diet are worth the cost or simply too expensive when on a restricted budget. Asta also highlighted another one of Parke’s discussed “assumptions” by raising the point on prohibited food stamps use for Safeway grocery delivery. She shined a light on the issue of convenience and how this is an essential consideration in affordability and health. These comments combined show how a tool like a Thrifty Food Plan calculator might not very useful without sharing some basic assumptions about food and health.