It looks obvious

MATTHEW REICH is a baker dedicated to natural ingredients. He prefers butter in the cookies and brioche he turns out at Tom Cat Bakery in Long Island City, Queens, and like many professional cooks he applauds the public health effort to get artificial trans fat out of food.

But, in a twist of science, the law and what some call trans-fat hysteria, Mr. Reich and other wholesale bakers are being forced to substitute processed fats like palm oil and margarine for good old-fashioned butter because of the small amounts of natural trans fat butter contains.

Some researchers believe that the trans fat that occurs naturally in butter, meat, milk and cheese might actually be healthy. But to satisfy companies that want to call their foods completely free of trans fats, bakers like Mr. Reich are altering serving sizes, cutting back on butter and in some cases using ingredients like trans fat-free margarine.