(USA TODAY) -- Danone, Unilever and Nestle -- companies that produce everything from frozen dinners to iced tea, baby food and ice cream -- are the three best large firms worldwide when it comes to offering products that address both the problems of obesity and poor nutrition, says a report out Tuesday.

The first edition of the global Access to Nutrition Index is based on a review of 25 of the world's biggest food and beverage manufacturers. It looks at their corporate nutrition-related policies, their formulation of healthier affordable products, informative nutrition labeling and responsible marketing.

The index was developed by the Global Alliance for Improved Nutrition, a non-profit with funding from the Bill & Melinda Gates Foundation and the Wellcome Trust. It was developed with input from nutrition experts and others, and research was conducted by an independent firm. The rankings and report are meant to be a benchmark of corporate practices, not just a look at the company's portfolio of products.

"Obesity and undernutrition affect over 2 billion people and threaten a global health catastrophe," said Inge Kauer, the index's executive director. She calls the report "an urgent call to action" to food and beverage makers to make improved nutrition part of their business strategies. "It is not only good for public health, it is a business imperative and key to their long-term sustainability."

She says the index "encourages companies to adopt a deliberate approach to the development of nutritionally improved options for consumers. Over time, these changes will have a significant, positive impact on public health."

While some companies ranked slightly better than others, all the world's largest food companies "can do substantially more to improve consumers' access to nutrition," the report says. The top three companies scored from 6 to 6.3 on a 10-point scale.

"Our aim is to enhance the quality of people's lives everywhere by offering tastier and healthier food and beverages, and encouraging a healthy lifestyle," says Hannah Coan, a spokeswoman for Nestl.

"PepsiCo has made great strides to transform our food and beverage portfolio in recent years to meet growing demand for health and wellness offerings, and we'll continue to build on the progress we've made to give consumers around the world the options they're seeking," says Jeff Dahncke, a spokesman for PepsiCo.

How did some companies that make ice cream, mayonnaise and soda make the top half of the list?

Just about every food company has products that go from worse to better when it comes to nutrition, and an index is a pretty hard thing to do, says Kelly Brownell, director of the Rudd Center for Food Policy and Obesity at Yale University and a member of the expert group that provided guidance on the development of the index.

"It's a challenge to come up with a score when a company could have many thousands of products. I give them high marks for courage for undertaking a difficult but very important task," he says.

"Companies can crow about making this little change and that little change, but having something that can address what they are doing overall is a very good start. With time, the index will get refined, and you'll have a better sense of what might be happening overall."

The report lists some key recommendations, including that companies should:

Develop clear and measurable objectives and targets on nutrition.

Implement a strict, comprehensive policy on marketing to children that applies to all media channels and all countries in which the company operates.

Use the experience, skills and scale of their core business to address undernutrition.

Make sure that products formulated to meet the needs of lower-income consumers, at risk for poor nutrition, don't increase the risk for obesity and diet-related chronic diseases.

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