03/09/2011 08:10 am ET | Updated May 25, 2011

Healthy Food Costs More--A Myth?

The conventional wisdom is that more nutritious foods cost more. Here in the proverbial nutshell (walnuts score a deservedly impressive 82 on the 100-point NuVal scale, so let's make it a walnut shell) is what's right, wrong, and downright ugly about this persistent bit of prevailing perception.

What's right is what made it conventional wisdom in the first place. In the modern food world, government subsidies are largely tied up with mass-production of crops used for purposes other than feeding people. Corn, for instance, is subsidized both for use in fattening feed animals which are in turn consumed by people, and for production of such derivatives as high-fructose corn syrup. Soybeans are subsidized, and put an astonishing variety of uses -- many having nothing to do with the nourishment of man, or beast.

Where the subsidies have not gone traditionally is to the most nutritious foods, such as vegetables and fruits intended for human consumption. It is perhaps ironic that the foods best suited to extend the 'shelf life' of human beings tend to have the shortest shelf life themselves. The converse, of course, is also true; some highly processed, glow-in-the-dark foods are all but immortal, while conspiring against the longevity of those consuming them.

The frailty and short shelf-life is among the factors that tend to make produce pricey, in the absence of subsidies. Spoilage happens, and cuts into profit margins; higher prices compensate. Produce is also subject to the vagaries of climate, and the price built into bumper crops must account for the years when an early frost or lack of rain wrought devastation.

Other high-cost, highly nutritious foods are subject to these and related considerations. By definition, wild salmon is ... wild, and thus much less reliable than, say, chickens. They must also be shipped long distances from where they are caught. Crops can fail, fish can be hard to find -- but marshmallows, chips, and cookies tend to be perfectly reliable. And thus, less costly.

But there is, as well, a downright ugly, hidden face to the cost of nutritious food. Namely, some food pretends to be nutritious, presumably so that a premium may be charged for it! This is truly ugly because the result is as follows: a health-conscious shopper is hoodwinked into thinking something is more nutritious when it is less, and spends more for the privilege of the deception. A classic addition of insult to injury, if you ask me.

How do I know this to be true? Well, having been devoted to the world of nutrition for 20 years or more, I have long had this perception. But my focus has certainly sharpened since the launch of the NuVal system. NuVal has now scored the overall nutritional quality of well over 90,000 foods. Along the way, we have seen innumerable examples of food products in almost every conceivable category that sport front-of-pack messages about better nutrition (e.g., lower fat, lower sodium, lower sugar, more vitamins, more whole grain, etc.) but that are actually less nutritious overall.

In one instance, we saw the nutrition score decline when a popular children's cereal came out in a "1/3 less sugar" version. It indeed had 1/3 less sugar, but it also had a lot more salt, a lot less fiber, less whole grain, more harmful fats and so on. A fancy multigrain bread will charge you a premium, but may have no more "whole" grain than white bread, and less than a humbly packaged, far less expensive whole wheat bread.

The average NuVal score for regular peanut butter is about 20. The average score for fat-reduced peanut butter, for which health conscious and "choosy" moms will pay a premium is a 7! A bit of healthful oil is taken out, while copious additions of sugar and salt are made. The front of the jar is mum on that topic.

But let's move on to what is merely wrong with the conventional wisdom about nutrition and cost.

Having long heard the two were linked, I did what researchers tend to do; I asked, where are the data? It turns out there are hardly any. So we set out to get some.

We devised a study, the results of which were just published in Public Health Nutrition, in which we sent a volunteer shopping in some typical U.S. supermarkets with criteria for more and less nutritious foods based on our Nutrition Detectives program. We asked the volunteer to buy equal numbers of products meeting, and failing, the criteria in diverse food categories. We then used NuVal to confirm that the seemingly more and less nutritious products truly were just that -- and we then compared the prices.

NuVal, which has itself been validated against actual health outcomes in over 100,000 people, confirmed that the Nutrition Detectives clues reliably distinguished more from less nutritious foods. And these two groups differed in price ... not at all. Sometimes the more nutritious foods were more expensive, sometimes less. Except in the produce aisle, price and nutrition do not correlate in the supermarket. The trouble is not really that more nutritious foods invariably cost more -- it's that most people have trouble identifying the truly more nutritious foods in the first place.

Cost is still a barrier, of course -- and some of the least nutritious foods do offer the most calories for the buck. We need to address this with policies -- such as linking food price directly to objectively measured nutritional quality, especially for those struggling financially, such as SNAP program participants. We have the means to do this, and should put it to the test.

We need to make an objective measure of nutritional quality available to all, so that the false perception of nutrition and cost is dispelled. Often you can trade up nutritionally at no increased cost.

Fundamentally, though, we need a new societal perspective on the value of food. Throughout most of human history, calories were relatively scarce and hard to get. More calories per dollar was a logical metric for food value in such a world.

But that is no longer our world. Ours is a world of epidemic obesity, and more calories per dollar simply means the chance to gain more weight at no extra charge. Many people are willing to spend a fortune to lose the pounds they gained for free! Perhaps it's time to recognize that nutrition per dollar is the better measure of value.

Supersize me and my kids? No thanks. Supervitalize us? We'll take it -- and at no extra charge, please!

Dr. David L. Katz;