By Mike Pomranz
Updated April 29, 2015
Credit: alamy

Counting calories has always been a popular plan for weight management. But a recent New York Times report calls into question just how accurate the calorie numbers on food labels really are. The potential good news: For some items, the actual number of calories is probably lower than the label states.

Experts believe that the most common method for assessing calories overstates the number of calories in foods that are high in protein and fiber, possibly by as much as 25 percent. “This is especially misleading for those on a high-protein, high-fiber diet, or for diabetics,” Geoffrey Livesey, the head of Independent Nutrition Logic, a nutrition consulting company in Britain, and a nutrition consultant to the United Nations, told the Times.

The problem, at its most basic level, is that the current system (which the Times points out was originally created back in the late 19th century) burns foods to see how much energy they contain. What it doesn’t take into account is digestion. High-protein foods like meat and nuts are harder to break down, so the body burns more energy consuming them. Additionally, some foods don’t get fully digested at all, meaning portions of those items’ calories simply get excreted. Nuts are the least accurate when it comes to current calorie counts, probably being about 25 percent too high, according to research by David Baer, a nutrition scientist at the US Department of Agriculture. Unfortunately, the calorie estimates for foods that are high in processed carbohydrates, like junk food, are far more accurate.

Despite so many experts acknowledging the issue, many are reluctant to change the current system for a multitude of reasons. Some say lower calorie numbers on products might send the wrong message that people can eat more. Plus, overhauling the whole system would be “a massive administrative and political undertaking,” said Rachel Carmody, a postdoctoral researcher at the University of California, San Francisco, and changing it could “cause a crisis of confidence for consumers.”

But don’t lose heart. “On average, the system is right, but on individual foods, it’s not right,” said David Klurfeld, program director for human nutrition at the Department of Agriculture. Just take the specifics with a grain of salt—which is very low in calories.