The case against trans fats is not new. For years, health experts have been telling us to avoid them.
And as retailing behemoths such as Wal-Mart have committed to the removal of all remaining, industrially produced trans fats in the products they sell, the food industry has stepped up its pace to reformulate its offerings.
The Grocery Manufacturers Association says the food industry has already reduced its use of trans fats by more than 85 percent. Even Crisco is now made without partially hydrogenated oils.
Now, the Food and Drug Administration is expected to take action soon to phase out much of the remaining trans fats in the food supply. The agency first announced its plan back in 2013. And, any day now, the FDA is expected to announce a final rule that could amount to a near ban of trans fats.
"The time is long overdue to get trans fats out of the food supply," says Michael Jacobson of the Center for Science in the Public Interest. He nudged for a mandatory labeling of trans fats on food packages, which has been in place since 2006.
So, where do we still find trans fats in the food supply? The labels of ready-to-bake pie crusts, baked goods and microwave popcorn are a good place to look.
Also, there are low-levels of trans fats in lots of foods — levels that fall below the threshold for labeling. As my colleague Eliza Barclay has reported, zero trans fats doesn't necessarily mean zero.
The FDA allows companies to list 0 grams on the label even if the food contains up to half a gram of trans fats. In other words, If a packaged food has less than .5 grams per serving, it can be labeled as trans-fat free.
So, if you want to avoid these trace levels, you've got to scan the ingredient list. If you see partially hydrogenated oils listed, you know there's a small amount of trans fats in the food.
And here's a little history lesson in how trans fats came to be: As my colleague Dan Charles has reported, in the early 1900s scientists worked out a way to add hydrogen atoms to a molecule of oil. In essence, that process converted liquid vegetable oils into solid fats.
After this discovery, the era of baking with Crisco and margarine began.
But, decades later, scientists began to document the damaging health effects of partially hydrogenated oils. Turns out, the ubiquitous use of trans fats was wreaking havoc on our cardiovascular systems.
Trans fats "raise bad cholesterol and lower good cholesterol," explains Dariush Mozaffarian, a cardiologist, epidemiologist and dean of the nutrition policy and science school at Tufts University. And that's not all, he says.
As Mozaffarian explains, trans fats also raise inflammation and worsen the health of blood vessels. "There's really not any other fat that has this constellation of harmful effects," he says.
The food industry has moved to reformulate many foods. Manufacturers have turned to alternative fats, such as palm oil and blends of vegetable oils. From a health perspective, that's an improvement, Mozaffarian says.
"Any natural replacement is superior to partially hydrogenated vegetable oil — whether it's butter, palm oil or blends of oils," Mozaffarian says.
When the FDA issues its final rule, it will likely move to revoke the GRAS (Generally Recognized As Safe) status of trans fats. And this could pose a problem for manufacturers that still have small amounts of partially hydrogenated oils in the products they sell. For instance, it could open them up to lawsuits.
The Grocery Manufacturers Association told us in a statement that "we share FDA's goal of reducing trans fatty acids in the diet." But the group is preparing to file a petition. "The food additive petition currently in development will help us to achieve this shared objective," the GMA statement says.
It's possible that the Grocery Manufacturers Association may ask for more flexibility in meeting the goal.