Feb. 9, 2017 -- As artery-clogging trans fats continue to disappear from foods, one of the fats replacing it is coming under fire: palm oil.

Palm oil is found in many foods, including margarines and spreads like Nutella, peanut butter (Jif, Smart Balance and others), and baked goods, including Girl Scout Cookies and Dunkin' Donuts.

A European safety agency has said that substances produced when palm oil is processed at high temperatures may cause cancer, based on animal studies. Experts already know palm oil is not the healthiest oil for your heart, and environmentalists have long warned that the rising demand for palm oil is jeopardizing the world's rainforests and endangering some animals.

Nutella's maker, Ferrero, is fighting back with an advertising campaign saying that its palm oil spread can be part of a healthy diet. Like other companies, it says it is using the oil in a safe way while working to minimize deforestation.

Palm oil comes from the palm tree fruit and is one of the few vegetable oils high in saturated fat, says Alice Lichtenstein, a senior scientist and director of the Cardiovascular Nutrition Laboratory at Tufts University's Jean Mayer USDA Human Nutrition Research Center.

A 2015 FDA rule requires food manufacturers to eliminate trans fats in 3 years. As trans fats are being phased out of foods, the demand for palm oil has modestly increased, says Robert Collette, president of the Institute of Shortening and Edible Oils, an industry group. It gives texture and volume to baked goods and is also used in margarines and spreads, frostings, icings, and candies.