SARATOGA SPRINGS, N.Y. — At 170 calories per serving, Kathryn Mora figured the spaghetti was harmless. So she slurped away, eating her fill.
A closer look at the nutrition label destroyed all those warm comfort food feelings: A serving was just an eighth of the box — not the whole thing.
“I can eat the entire box, like that,” said Mora, snapping her fingers.
A common pitfall when checking nutrition labels is failing to factor in serving size, according to a small study by Vanderbilt University researchers. And even when people do, they often miscalculate how much they’re eating. Americans’ inability to understand portion control is one reason cited for the country’s climbing obesity rates.
Vanderbilt’s study was conducted between June 2004 and April 2005 when the low-carb craze was at its height, so many of the questions involving serving size focused on carbohydrate counts. Researchers found only about a third of the volunteers correctly estimated how many carbs were in a 20-ounce bottle of soda.
“Most people don’t realize those have 2.5 servings,” said Dr. Russell Rothman, lead author of the study.
Though less frequent, the same mistakes could happen when estimating calories, Rothman said. So someone drinking a 20-ounce bottle of soda may think they’re getting just 100 calories when they’re actually guzzling 250.
In the study, similar mistakes were made on other foods.
Those with lower education levels were more likely to misinterpret labels, but mistakes were made across the board.
Set by the federal Food and Drug Administration in 1993, serving sizes are often smaller than most Americans eat in a sitting. And bigger packaging over the years may have distorted perceptions.
A serving size for a drink, for example, is 8 ounces. But a can of soda has 12 ounces and most bottled sodas now contain 20 ounces or more.
With two-thirds of Americans overweight or obese, the FDA recently solicited suggestions on how to tweak nutrition labels and serving sizes to make them more useful.
The food industry has responded to the confusion in recent years with a slew of products that help people size up a serving. Chips, crackers, cookies and pudding now come in handy 100-calorie packs, and single-serving packaging has exploded in popularity.
The Vanderbilt study, which surveyed 200 people, found that overall, people answered more than two-thirds of the questions about nutrition labels correctly.
Many were confused about the meaning of “percent daily values” based on a 2,000 calorie diet. However, by far the most common mistake involved serving size; many people failed to notice the serving size number and others just miscalculated.
A pint of ice cream, for example, has four half-cup servings — but many of those in the study interpreted that to mean one serving was half the container.