A new study has shown that about 9 percent of packaged foods in the United States contain trans fats. Of those, the vast majority (84 percent) were listed as containing no trans fats. And that's all perfectly legal according to the FDA.

A significant body of research has shown that the consumption of partially hydrogenated oil (trans fat) contributes to heart disease. But trans fats are still perfectly legal here in the United States. You may be saying to yourself, as long as people know what they're consuming, there shouldn't be a problem. But in many cases, people don't know. Because under current FDA rules, products can have up to 0.5 grams of trans fat per serving and still claim that their product is free of trans fat.

From the new study at the CDC:


Our analysis demonstrates that industrial trans fat is still common in US packaged foods, particularly in some food categories. These findings, which are consistent with FDA research findings, provide evidence of the prevalence of industrial trans fat and show that most products that contain [partially hydrogenated oils] are labeled as containing 0 g of trans fat (84%). This labeling is cause for concern because consumers, seeing the 0 g trans fat on the Nutrition Facts label, are probably unaware that they are consuming trans fat.

Frustratingly, the study only breaks out the findings by product category and doesn't specify which brands advertising themselves as trans fat-free actually contain some trans fats. But of the foods they looked at, we can deduce which products you may want to steer clear of. The seasoned packaged potatoes, for instance? A whopping 66 percent of those that were labeled as containing no trans fats actually did.

Which leads us to questions about other products like "no sugar added" Naked Juice that contains more sugar than Pepsi. Is it really all "naturally occurring" sugar in those drinks? Or are they perhaps utilizing labeling loopholes? [via NPR's The Salt]

Image: Food items which contain trans fat are shown on November 7, 2013 in Chicago via Getty

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