The federal government is finally walking back its dietary guidelines on fat consumption. This year, federal bureaucrats are engaging in a periodic rewrite of the Dietary Guidelines for Americans, and it appears this time they may finally be listening to what the research is telling them — because the science isn’t settled.

Since 1980, the assumption held by the federal government was that a reduction in total fat content would reduce the risk of heart disease, which has long been the number one killer of Americans. As years passed, however, independent scientists discovered that it wasn’t necessarily a reduction in total fat that was at issue, but better management of the sources of fat in one’s diet.

For decades, federal bureaucrats led people to believe they could reduce the risk of heart disease if they lowered their fat intake to only 20-35% of their diet, regardless of the source. As a result, people ate more carbohydrates and sugars to fill up, which led to higher rates of obesity. People also reduced their consumption of beneficial monounsaturated and polyunsaturated fats like fish and nuts. Consequently, heart disease continued to rise.

The federal government also told Americans that whole milk was bad, and people began drinking more skim and low-fat milk. Unfortunately, in their zeal to eat less fat, people neglected the beneficial nutrients whole milk had to offer. Children in particular missed out because the nutrients found in whole milk have been proven to be highly beneficial to the body during growth phases.

“If we are going to make recommendations to the public about what to eat, we should be pretty darn sure they’re right and won’t cause harm,” said Dariush Mozaffarian, a cardiologist and epidemiologist at Tufts University. “There’s no evidence that the reduction of saturated fats should be a priority.”

Penny Kris-Etherton, professor of nutrition at Penn State and the chair of the American Heart Association’s nutrition committee, added, “A lot of people still look at how much fat [is in foods], and we’re now saying don’t focus on that: Look at the quality of fat you’re consuming.”

It turns out the milk fat government said was bad for us actually lowered incidents of heart disease. Studies have been mounting for years disproving the long-standing guidelines that the Department of Agriculture and the Department of Health and Human Services refused to revisit. Perhaps they believed the science was settled. It’s just one more example of a terrible trend by the government to entrench itself in a debate in which it really should have no voice.

Just why we are listening to the federal government tells us regarding our diets is anybody’s guess. Being elected to public office or being appointed to a government board does not automatically make one an expert in any field, particularly medicine.

Now, consider the “settled science” on climate change and other similar arguments over the production and consumption of energy. Democrats claim they want to free science in the name of scholarly debate, but they reject the idea that the driving force of science is discovery. It’s about analyzing data and looking at the evidence as it is currently understood, not arbitrarily announcing a conclusion, then looking for favorable data that fits the narrative while ignoring contrary evidence — all in support of massive government economic interference.

There’s a lot of money riding on the government’s actions. There is a huge cost in health care to be paid for the higher incidences of heart disease that resulted from wrong-headed government action. But the money doesn’t seem to matter. And no one is learning the lesson.

Michelle Obama’s crusade for healthier school lunches is based on the same questionable data that have backed the federal dietary guidelines for decades. The USDA estimates that school districts will have to pay $1.22 billion in new food and administrative costs in Fiscal Year 2015. Additional costs for FY 2014 were $362 million. Rather than let local school nutrition experts determine what works, public schools across the country are forced to listen to the First Lady, whose own experience in the matter extends to planting a vegetable garden on the White House grounds.

But hey, it’s “settled science.”