Preventive Medicine Column
Dr. David L. Katz
I recently had jury duty. Perhaps that’s why, in response to an announcement by the FDA that provisions in the health care overhaul call for extending mandatory calorie labeling beyond chain restaurants to other venues, including trains, planes, and movie theatres, I find myself wanting more than some truth about food. I want nothing but the truth. I want the whole truth!
I support posting calories on menu boards, but don’t feel it goes nearly far enough.
You doubtless recall that school yard brain teaser: which weighs more, a pound of feathers or a pound of iron? But what about the follow-up question: which would you rather drop on your foot?
Weight is not the only relevant metric, clearly. Just ask the broken toe.
So, too, with food- where calories count, but they are far from all that matters. Calories tell a truth about food, but nothing remotely like the whole truth.
For instance, let’s consider two orders of French fries. One is small- and, say, 150 calories; the other is large, and say, 350 calories. The calorie difference might encourage you to go with the smaller order. But now imagine that the small order of fries was prepared in trans fat, and the large order was prepared in a healthful oil. Calories don’t tell all.
Calorie counts are potentially valuable in helping you see the cost- in calories- of larger portions. But they tell you nothing about other costs, or the return on that investment, in terms of either nutrition, or the fullness and satisfaction you are hoping to achieve. And the evidence suggests that while providing a reality check that does, at times, encourage the more moderate choice- the effect of posting calories is variable, and modest.
One likely reason is that people don’t generally eat to fill a calorie quota- we eat to fill ourselves! If you like a large burger and fries, you might be compelled with calories on display to order a smaller version of each- but you might, then, finish and still want more. So maybe you order another, or maybe you eat something else just a little while later. Calories may have gone down at the time of the initial selection, without going down for the day.
Calorie-only messages may compel people to choose smaller portions of less nutritious food. And here’s one of the many problems with that: in general, less nutritious foods propagate overeating, while more nutritious foods help us fill up on fewer calories! If you reduce calories by reducing portion, but not by improving nutrition, there’s a good chance you’ll be hungry again soon- and back in line to buy more calories. Wholesome, highly nutritious foods are at times high in calories- walnuts, for example- but they tend to induce a lasting feeling of fullness that helps control total calorie intake in the end.
A very small order of fries- or for that matter a small soda- might well have fewer calories than a serving of grilled salmon, or walnuts, or avocado. That doesn’t make the soda a better choice. The soda offers no valuable nutrients. The ratio of nutrients to calories in salmon, walnuts, and avocado is very, very high. Yes, there are calories- but if that is your investment, there is a large return.
My view is that information about how much food we eat- the calories- cannot be instead of information about what food we eat, namely its overall quality. Eating foods of greater overall nutritional quality will make every calorie count, and help you fill up on fewer calories. I know this not just because I live this way, but because I have written not fewer than three books that extensively address the issue of nutrition and satiety.
There is a saying that when you have a hammer, the world can look like a nail. Perhaps so- and maybe I think a summary measure of overall nutritional quality is so valuable because I happen to have a very good one in the NuVal system (www.nuval.com). But I tend to think of NuVal just the other way around: nails were protruding everywhere, and a hammer was needed, so a group of us dedicated to public health built one.
Calories can tell you how to eat less. A summary measure of overall nutritional quality can tell you how to eat better. My ideal would be menu boards that list both calories, and a NuVal score (1 to 100; the higher the number, the more nutritious the dish). That way, you could see at a glance that there are larger and smaller portions of higher and lower quality foods. Two dishes might have the same calories, but vary widely in nutritional quality; or vice versa. Were a food laced with arsenic, it would, I trust, provide scant comfort to know that your serving were a mere 200 calories. Trans fat, certain saturated fats, excess sugar, and excess sodium are less potent, but more prevalent toxins than arsenic- and similar thinking should apply.
So- fresh from jury duty, I weigh in for doing more than just weighing feathers and iron, or French fries. What you drop on your foot, or put in your mouth, matters. We need the whole truth on display for decisions that are fully informed, rather than half-baked.
Dr. David L. Katz; www.davidkatzmd.com