[dr huer]

Hydrogenation of vegetable oils, which reduces the degree of unsaturation, started a hundred years ago. The process makes cis fats, and trans fats. Seventy years ago I read about hydrogenation as being a valuable advance in food processing in "Creative Chemistry", by E. E. Slossen. We used them abundantly during WW 2 to substitute for unavailable butter. I am yet to see the "abundance" of scientific evidence that they are bad for you. If they really really very bad it would have been obvious 50 years ago.

[Valin]

But they are bad for you. and what's more the cause global warming!

[Rockingham]

Science advances and often revises earlier judgments, and not all ills have obvious causes. The case against trans fats is now persuasive if not conclusive. As for trans fats being safe because they have been used for a long time, consider the results of the US Army autopsy studies on KIA's.

For healthy young men who died in combat, in WW I, the arteries were clean -- in an era of diets rich in butter, egg, red meat saturated fats. In WW II, the arteries were beginning to show deposits. By Viet Nam, the arteries of young KIAs were, by comparison, starting to be significantly thickened and riddled with deposits. Was this the results of cigarettes or trans fats? Or something else? Since cigarette usage was similar between WW II and Viet Nam, trans fats are the more likely cause -- all those oreos, snack cakes, margarine, and so on.

There is an abundance of medical evidence to the same effect. Take a look at Pub Med and Medline for specifics.