DES MOINES, Iowa (AP) — Once snubbed, whole-fat milk, yogurt and other dairy products are finding their way back into our refrigerators, thanks to a growing interest in "whole foods" diets and new evidence that full-fat dairy products can be good for us, experts say.

The trend is showing up in milk sales, both nationally and in Des Moines, industry data show. Whole milk sales in Des Moines climbed 9.6 percent last year over 2014; nationally, they climbed 4.5 percent.

At the same time, fat-free milk sales in Des Moines dropped 9.5 percent, and nationally, they shrank 12.3 percent, according to data provided by Dairy Management, a marketing group for the industry's 45,000 U.S. dairy farmers.

Chicago analytics company IRI collects the data. Statewide sales information wasn't available.

"Full-fat dairy products used to be seen as taboo. We were told we should cut them out of our diet," said Ruth Litchfield, associate professor of food science and human nutrition at Iowa State University. But "we're realizing that fat can be good."

Litchfield said the federal dietary guidelines still recommend that Americans consume low- or fat-free milk, yogurt and cheese. The concern: Foods that contain saturated fat — such as whole milk, cheese and butter — can raise cholesterol levels that contribute to heart disease.

But some new studies are challenging that perspective, Litchfield said.

"There is some research that's coming out that shows consumption of whole-fat dairy is decreasing risk of Type 2 diabetes, decreasing risk of cardiovascular disease, decreasing risk of certain kinds of cancer, and people who consume whole-fat dairy products are less obese," she said.

Researchers are exploring whether it's the "dairy itself or their eating pattern as a whole," Litchfield said.

"People who consume dairy products also tend to have other healthy behaviors," she said. "They're less likely to be smokers, they're more likely to be active, and they're more likely to consume whole grains."

Researchers also are weighing whether milk could trigger a "certain expression of genes" that have health benefits — or whether milk's "pre- or probiotics" improve "gut health," which can affect chronic health diseases, Litchfield said.

One thing is clear: Dairy products are good sources of calcium, vitamin D and potassium — three of the four nutrients federal dietary leaders say Americans are consuming inadequate amounts of and have "real relevant health implications," Litchfield said. The fourth is fiber.

Kim Peter, marketing director at Anderson Erickson, sees consumers "embracing full-fat food." Whole milk sales at the Des Moines dairy climbed 7 percent last year over 2014.

"Whole milk doesn't carry the stigma that it did in the '80s and '90s," when consumers were urged to cut fat wherever possible, Peter said.

Peter, Litchfield and others say the growing popularity of diets that focus on "whole foods" — or foods with little or no processing — is contributing to the sales of higher-fat products.

Litchfield said consumers may see whole milk as less processed. They want "foods that are more natural," she told The Des Moines Register (http://dmreg.co/28KrFZc ).

And consumers understand that manufacturers can replace saturated fat with sugar, both for flavor and as a preservative to improve shelf life.

"Any cardiovascular benefit you got from decreasing your saturated fat, you're not getting . because of sugar," Litchfield said.

Federal dietary guidelines limit sugar intake to no more than 10 percent of daily calories, a recommendation that means many consumers need to cut their sugar consumption.

Peter said Greek yogurt is another full-fat product that's growing in popularity. The company started making yogurts in the 1960s and Greek yogurt in 2010.

Nationally, sales of all types of Greek yogurts climbed last year over 2014, but sales of full-fat Greek yogurt nearly doubled, according to Dairy Management and IRI.

Stephanie Cundith, a dietitian with the Midwest Dairy Council, said consumers may feel more satisfied from higher fat content in milk and yogurt. That could lead to fewer overall calories consumed.

And Greek yogurt has double the protein of traditional yogurt, Cundith said.

Growing interest in gourmet cooking shows might be lending to an interest in higher-fat dairy products as well, experts say.

U.S. per capita consumption of butter, for example, hit a 40-year high, at 5.6 pounds, last year, industry data show. In 1997, per capita consumption was 4.0 pounds.

Peter said Anderson Erickson saw sales of heavy whipping cream climb 5 percent in 2015 over 2014.

She sees the dairy's products feeding another consumer trend: Buying local.

Peter said yogurts at the company are made in small batches with milk that comes from Iowa dairy producers.

Litchfield and Cundith said consumers still need to keep calories in mind when eating full- or higher-fat products.

"We need to think in context of our total diet," Litchfield said. "We need to keep our fat intake to 30 to 35 percent of calories. About 10 percent should be the limit for saturated fat.

"Having some full-fat dairy along the way is appropriate, as long as your total intake is moderate," she said.