Today, a patient asked me a question that started me thinking about Carl Bialik’s recent Wall Street Journal editorial on food labels and the metric system.
My patient was trying to determine the quantity of a meal replacement supplement she could have at lunch based on her carbohydrate allotment of 45 grams. She read on the label that one serving was 274 grams and provided 33 grams of carbohydrate. She wanted to know if her calculation of having 1/7 of the supplement was correct.
The patient had confused the weight measure of one serving of the product with the number of carbohydrate grams in the product. She wasn’t alone in making this error; many patients have the same difficulty. People in general are not comfortable with thinking about food in gram amounts.
As Bialik so ably pointed out, our country has had a dismal showing on metric math.
Outside the world of engineering, science and, of course, dietetics, the US population has made every effort to avoid learning anything about the metric system.
We have done a great job putting our heads in the sand. Other than the food label, few consumer goods are sold in meters, kilograms or liters.
Without a conceptual understanding of size comparisons in the metric system, consumers can’t attach any value to the number of grams of nutrients in food. Without this base line knowledge, the difference between a product containing 3 grams of fat versus 25 grams has no intrinsic meaning.
The food label was designed to stand on its own as a public health measure affording to help people make better nutrition choices. The average American consumer is supposed to be able to pick up any grocery item off the shelf, examine the label and make an informed decision about its nutrition value.
Yet, one of the things dietitians frequently have to do is teach patients to read a food label. Most people I have worked with are familiar with the label, but fewer than you would think have a good idea of how to use the label to shop advantageously
One solution to this problem is to change the units of measure from a metric base to English units. That still wouldn’t fix everything that makes food label reading difficult, but it may help people visualize what they are putting into their mouths and hence their bodies. It certainly is easier to visualize becoming a bit queasy about eating the equivalent of 91/2 tablespoons of fat versus approximately 92 grams when you have four slices of pizza.
On the other hand, it would certainly be a step backward in the nation’s overall scientific literacy, since many American professions—not to mention the rest of the world—uses the metric system on a daily basis.
Let us know what you think- would replacing the gram amounts on the nutrition fact panel to measuring spoons and cups make it easier to read and more relevant to making healthy decisions in the grocery store? Or do you think it’s time we start using metrics?