Dietary advice can be confusing. Is it OK to eat meat and eggs? Is fat in or out? What about grains? How much salt?
An advisory committee's recommendations for the nation's dietary patterns are due soon, and some advice may be changing. The committee is expected to downplay the importance of lowering cholesterol intake and may put less emphasis on eating lean meats. The panel could also tweak its recommendations on exactly how much salt is too much and put limits on sugar consumption for the first time.
Still, despite some revisions, the main advice never changes: eat more fruits and vegetables and whole grains, and eat less saturated fats, salt and sugar.
The Agriculture and Health and Human Services Departments will use the advisory committee's report to write the final version of the 2015 dietary guidelines, due by the end of this year.
A look at the upcoming dietary guidelines, and what they mean for consumers:
Why they're important
The dietary guidelines are issued every five years. The federal government uses them to set standards for school lunches and other federal feeding programs, and they serve as the basis for information on the nutrition facts panel on the backs of food packages.
They're also used to create the government's "My Plate" icon, which replaced the food pyramid and recommends a variety of fruits and vegetables, whole grains, lean proteins and low-fat dairy.
Doctors and nutritionists use the guidelines when giving advice, and food companies use them to make claims about their food.
Evolving with science
The guidelines evolve as science evolves. Take cholesterol.
In December, the advisory panel said in its preliminary recommendations that cholesterol is no longer "considered a nutrient of concern for overconsumption." That would be a change from previous guidelines, which said Americans eat too much cholesterol. This follows increasing medical research showing how much cholesterol is in your bloodstream is more complicated than once thought, and depends more on the kinds of fats that you eat. Medical groups have moved away from specific targets for cholesterol in the diet in recent years.
It's unclear if the recommendation will make it into the final guidelines. Dr. Robert Eckel, a professor of medicine at the University of Colorado in Denver who is a past president of the American Heart Association, says there's not enough evidence to make good recommendations on cholesterol right now, but "no evidence doesn't mean the evidence is no."
People can enjoy high-cholesterol egg yolks in moderation, he advises, but "a three- to four-egg omelet isn't something I'd ever recommend to a patient at risk for cardiovascular disease," he says.
There's also some new science on salt. The 2010 dietary guidelines recommend that people eat less than 2,300 milligrams a day. That is reduced to 1,500 milligrams for some people at risk of heart disease.
A 2013 report by the Institute of Medicine said that while lowering salt intake is important for heart health, there is no good evidence that eating less than 2,300 milligrams a day of sodium offers benefits. The advisory panel's discussions hint that they may not include the lower recommendation for certain groups.
While they are based on dietary science, the guidelines aren't immune to politics. This year, the battles have already started over meat.
Current guidelines advise that people eat lean meats as a healthy way to get protein, but the advisory panel has debated whether lean meats should be included. In addition, the draft recommendations say a healthy dietary pattern includes fewer "red and processed meats" than are currently consumed. The meat industry called the draft recommendations absurd.
The committee has also discussed the idea of including sustainability as a dietary goal. The advisory panel said in its draft recommendations that there is "compatibility and overlap" between what is good for health and what is good for the environment.
A diet higher in plant-based foods and lower in animal-based foods is "more health promoting and is associated with lesser environmental impact than is the current average U.S. diet," the draft recommendations said.
Environmentalists have been pushing those recommendations, while Congress is pushing back. Language attached to a massive year-end spending bill enacted in December noted the advisory committee's interest in the environment and directed Agriculture Secretary Tom Vilsack "to only include nutrition and dietary information, not extraneous factors" in final guidelines.
What won't change
The "My Plate" isn't expected to change much - the guidelines issued at the end of the year will most certainly recommend putting fruits, vegetables, whole grains and lean proteins on your plate, accompanied by low-fat dairy.
In its draft recommendations, the panel said the problem it is trying to solve is high rates of "preventable chronic disease" and obesity.
The panel said the gap is an American diet too high in sodium, saturated fat, refined grains, added sugars and calories, and too low in vegetables, fruit and whole grains.