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Why you should trim some — but not all — of the fat from your diet

Milk is displayed on shelves in a New York City supermarket in 2014. (Spencer Platt/Getty Images)

Old guideline: Replace whole milk and full-fat milk products with fat-free or low-fat choices.

2015 guideline: Healthy eating patterns limit saturated and trans fats. Less than 10 percent of your daily calories should come from saturated fats. Foods that are high in saturated fat include butter, whole milk, meats that are not labeled as lean, and tropical oils such as coconut and palm oil. Saturated fats should be replaced with unsaturated fats, such as canola or olive oil.

Everything you need to know about what to eat/what not to eat

Many Americans have come to believe that saturated fat found in products like whole milk, butter and red meat is a dietary evil. But many nutritionists now say that judging food based solely on its fat content obscures other possible health benefits. And a recent study based on 10 years of diet and health records for several thousand patients found that people who consumed more milk fat had lower incidence of heart disease.

Such results undercut the idea that just spurning saturated fat can make people healthier. While numerous studies over the years have appeared to show that saturated fat raises the risk of heart disease, new research suggests that you can't just replace it with "low fat" carbs like bread and cookies. Far better is switching to the fats found in nuts and fish.

Here's a look at where we get our saturated fats, according to the new report:

The federal government's influential Dietary Guidelines for Americans are updated every five years, and the debate over saturated fats, red meat, caffeine and salt has been especially intense this time around.

[For decades, the government steered millions away from whole milk. Was that wrong?]

The guidelines are the basis of everything from school lunch programs to the diets promoted in bestselling books, but in recent years some scientists have begun to question the one-size-fits-all approach. A growing body of research supports the theory that a person's genetic makeup or microbiome (the organisms that live on or inside of you and help to make you who you are) plays a key role in how food affects the body -- and that the impact can be different from one individual to another. That work supports a more personalized approach to diet, which some researchers argue have argued is the future of nutrition science.

Here's a look at how much saturated fat we take in versus the recommended maximum limit, according to the new guidelines:

Read more:

Scientists have found another reason we should be drinking more whole milk

This diet study upends everything we thought we knew about ‘healthy’ food

Cutting sugar from kids’ diets appears to have a beneficial effect in just 10 days

Scientists (sort of) settle debate on low-carb vs. low-fat diets

Doritos, deconstructed (mesmerizing photos of the 34 processed ingredients in your favorite snack)

Hot topic: Could regularly eating spicy foods help you live longer?

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