Last month, the Food and Drug Administration proposed changing Nutrition Facts labels to make serving sizes reflect what people actually eat. Several studies support the changes, though some research suggests it’s going to take more for the public to make healthy choices.

Serving sizes have always been intended to represent what people actually eat, not what people should be eating. But the data determining current serving sizes is old – from the 1970s and 1980s – and people are eating larger portions than they did 30 years ago.

The proposed changes would mandate that some products often eaten in one sitting, such as a 20-ounce can of soda, be labeled as a single serving. Other packages would require a label with two columns. One column would show nutrition information for a serving and one would display information for the whole package.

As would be expected, FDA research supports the changes, though it suggests single-serving labels may be more effective than dual-column labels at helping people make healthy food choices.

Consumers found both single-serving labels and dual-column labels to be more useful, trustworthy and helpful in a 2012 FDA study. They also rated products with single-serving labels as less healthy than products with two-serving labels. Dual-column labels didn’t produce this same effect.

A study by marketing researcher Gina Mohr found similar results.

“We actually show consumers are more likely to choose the multiple-servings-per-pack item because they feel less guilty about consuming an entire package,” Mohr said.

The researchers showed study participants Nutrition Facts labels for various products, such as chocolate bars and granola bars, and asked how guilty they would feel after consuming the entire package. Some labels gave information for multiple servings, while others focused on a single serving. Health-conscious consumers were found to feel less guilty and be more likely to purchase products with multiple-serving labels.

Improved labels may be a step in the right direction, but only for consumers who actually use them.

A quarter of participants in an eye-tracking study reported that they almost always pay attention to serving size on Nutrition Facts labels, while the eye-tracking results found that less than one percent were actually looking at this part of the label.

Study author Daniel Graham’s more recent eye-tracking research suggests a front-of-package label may be the next step, finding front-of-package labels receive nearly five times as many views as side labels.

“People are just not exerting the effort to turn all of the boxes around,” said Graham, a psychologist at Colorado State University.

And effort is part of the answer.

Labels with more realistic serving sizes will be more accurate and fair to consumers, according to Keith Ayoob, a registered dietitian and pediatric nutritionist at the Albert Einstein College of Medicine.

However, he also notes that a label is just a tool.

“I think we have to give consumers accurate information and the best tools to use,” Ayoob said. “The consumer’s decision is then do I use it, or do I not use it.”