For those resolved to eat better in the new year, Yale School of Medicine researcher David Katz might have a solution.

NuVal, a system designed by Katz that assigns a numerical evaluation of a food’s nutritional content, is currently available at three different supermarket chains. Katz said he hopes the system will help Americans to make better food choices.

“As a physician who cares for patients, I’ve spent a lot of time over the last 20 years about helping people eat better,” Katz, the director of the Prevention Research Center at the School of Medicine, said. “But I’ve seen many people fail to implement nutritional advice. Out in the real world, they’d be fooled by marketing and the confusing details on the foods’ packaging.”

NuVal, which launched as a company in 2008, gives a score ranging from one to 100 for each food item in the store. In participating supermarkets, a food’s score is listed alongside the price for easy comparison between foods. The higher the score, the more healthful the food.

This practical, simple approach to presenting shoppers with dietary information should help them to improve their diets, Katz said. Despite the volume of nutritional information available to Americans, they struggle to make sound food choices, he added. For example, Katz said that his wife, whose knowledge of nutrition matches his own, once brought home four loaves of bread because she was not sure which was best.

“We have a huge, complicated modern food-scape, and people need a GPS,” Katz said.

For Katz, this meant creating a easy-to-decipher system of nutritional profiling. In early 2006, he convened a panel of nutrition experts to begin work on the system. The group reviewed scientific and research literature, as well as all other existing systems for judging the nutritional quality of food.

The team developed an algorithm to generate food scores, Katz said. High-quality proteins and a low ratio of saturated to unsaturated fats add to a food’s score, while foods that are calorie-dense and quickly raise blood sugar lower a food’s score. If a nutrient is strongly correlated with a serious health problem — for example, trans fats are linked to cardiovascular disease — the food’s score can also take a dive.

NuVal also takes into account less familar nutrients such as flavinoids, Katz said. As a result, NuVal can distinguish between the value of milk chocolate and dark chocolate, which contains more flavinoids.

Because NuVal has no political or industry influence, Katz said it is different from other systems. Research for the NuVal algorithm is funded by Griffin Hospital in Derby, Conn., a Yale-affiliated, not-for-profit community hospital. Other than a stipend for his research, Katz receives no further reimbursement for his work.

Maureen Murphy, the manager of consumer services and trends for the supermarket chain Price Chopper, said the chain chose to use the system because it has no industry connections.

“People can’t make major trades in nutrition, but they can make small nutritional changes,” Murphy said. “[With NuVal] you can do it one food at a time to compare between products.”

Murphy said she hopes the introduction of the NuVal system will also push manufacturers to rethink the nutritional content of their products. But this will not mean eliminating low-scoring foods from Price Chopper shelves, she added.

“We’re not trying to be a censor,” she said. “[Low-scoring foods] can fit in a healthy diet. It’s not about striving for a diet of all 100 or 90s.”

Ruth Comer, assistant vice president of media relations at the supermarket chain Hy-Vee, said she sees NuVal as an investment to help customers to make the right food choices. Since January 2009, Hy-Vee has used NuVal in all 228 of its retail stores.

A complete list of the 40,000 foods ranked by NuVal will soon be available online, Katz said. NuVal currently has contracts with Meijer, Hy-Vee and Price Chopper stores, he said. There are also plans to install the system at other supermarkets, Katz said, though he declined to say which ones.

The company also plans to launch the system in school cafeterias nationwide free of charge, Katz said.