AUDIE CORNISH, HOST:
It's the end of the line for trans fats. The Food and Drug Administration announced today that food companies have three years to remove all trans fats from processed foods. NPR's Allison Aubrey joins us to talk about how trans fats, which were once considered a healthy alternative to fats like butter, turned out to be bad for us. Hey there, Allison.
ALLISON AUBREY, BYLINE: Hi there, Audie.
CORNISH: So this sounds like it's an all-out ban. Am I reading that correctly?
AUBREY: Yes. What the FDA is saying is that trans fats, which are listed on food labels as partially hydrogenated oils, are not safe. The FDA is removing what's known as the GRAS status, which stands for generally regarded as safe, because they say the evidence is clear that trans fats are bad for us. I spoke to Tufts University's Dariush Mozaffarian who explained just how bad.
DARIUSH MOZAFFARIAN: They raise the bad cholesterol. They lower the good cholesterol but also raise inflammation, worsen the health of blood vessels. There's really not any other dietary fat that has this constellation of harmful effects.
CORNISH: So given what we've just heard, sounds like this was not unexpected.
AUBREY: That's right, not a surprise here. In fact, the writing has been on the wall for trans fats since about 2006. That's when the FDA began requiring food companies to disclose the amounts of trans fats in processed foods. And since that time, partially hydrogenated oils have really begun to disappear from the food supply. In fact, the Grocery Manufacturers Association says that the food industry has already reduced its use of trans fats by about 85 percent.
CORNISH: So let's go back in time here. Remind us where trans fats came from, why it took us so long to realize that they were bad for us.
AUBREY: Sure. Well, when trans fats entered the food supply way back in the early 1900s, no one had a clue that they were bad for us. In fact, industrial trans fats were touted as a real technological innovation. Their original purpose was to take really inexpensive, plentiful vegetable oils and make them into a solid fat that could be used for baking. So these fats that stayed solid at room temperature were very helpful to the packaged food industry. And by midcentury, they were found in everything from, you know, crackers to cookies and lots of snack foods. But decades later, after trans fats had become basically ubiquitous in the food supply, that's when studies started to show these bad effects.
CORNISH: So what's the industry's response to today's announcement?
AUBREY: Well, many of the products that once contained trans fats are now completely free of partially hydrogenated oils. This is true even of Crisco products. Manufacturers have moved to alternatives, such as palm oil. Now, at the Grocery Manufacturers Association, which is a trade group made up of about 300 food companies, released a statement today basically saying, hey, we're on board. We will use the next three years to complete this transition to alternatives. But they're also poised to ask the FDA for some exceptions. They may try to make the case that, you know, hey, at very, very low levels, trans fats in certain kinds of products are OK.
CORNISH: And you mentioned one alternative - palm oil - but I understand that has its own problems, right?
AUBREY: Well, the case against palm oil is really about how it is produced. There's been clearcutting of forests in Indonesia to produce palm oil, and those issues of the ecological footprint are ongoing but being addressed.
CORNISH: So in the meantime, what are the products that still contain trans fats?
AUBREY: Well, packaged cookies, crackers still contain tiny amounts. Brands of microwave popcorn, packaged cake icings, snack chips. If you see seasoned chips, the trans fats are used to get the seasoning to stay caked onto the chip. But the bottom line here is that there's already way less trans fat in the food supply than there used to be.
CORNISH: That's NPR's Allison Aubrey on the announcement today from the FDA that it will require food companies to phase out trans fats almost entirely within three years. Allison, thanks so much.
AUBREY: You're welcome, Audie.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.