Among the reasons the Center for Science in the Public Interest can kiss my ass

In the 1980s, some scientists began to associate heart disease with saturated fats, and in response, groups such as the Center for Science in the Public Interest and the National Heart Savers Association (NHSA) began to hound manufacturers for “poisoning America ... by using saturated fats,” and as a result “nearly all targeted firms responded by replacing saturated fats with trans fats,” as David Schleifer wrote in 2012 for the journal Technology and Culture.

At the time, many restaurants used beef fat for frying, which groups like CSPI believed was far worse than hydrogenated oils, based on the research of the time.
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(in the 1990's) Surprisingly, it was the same organization, CSPI, that later urged the FDA to add trans fats to food labels, and nutrition panels have been required to list the substance since 2006. Though American consumption of trans fat has declined precipitously in recent years, it's still common in food such as microwave popcorn, margarine, and some coffee creamers. But probably not for much longer.