Q. Your website states that certain meats contain trans fat. I was under the impression that trans fat is man-made and occurs only in things like hydrogenated & partially hydrogenated oils, not natural foods. Was I wrong about that?

A. In fact, all trans fats are not man-made! As you've discovered, some unprocessed foods such as beef and dairy can also contain small amounts of trans fats. These occur naturally when one or more of the hydrogen bonds of an unsaturated fatty acid molecule get twisted. But these naturally occuring are not the trans fats that everyone is so worried about.

For one thing, research suggests that naturally occuring trans fats do not have the same damaging health effects as the man-made trans fats found in artificially hydrogenated vegetable oils. (See this article on "Natural trans fats" for more details on the research.) Secondly, the amount of natural trans fats that we get from meat and dairy products is quite minor compared to the amount of man-made trans fats that we used to consume. 

I say "used to consume" because things are changing quickly on that front.  Due to a combination of legislation and consumer pressure, artificially hydrogenated oils are slowly disappearing from our food supply.  Manufacturers of processed foods, such as chips, snacks, baked goods, baking mixes, cereals, salad dressings, and sauces are removing all or most of the trans fats from their products.  Several fast food restaurants have reduced or eliminated trans fats in their French fries, fried chicken, and other foods. And many cities have enacted or are considering trans fat bans for all restaurants.  Hopefully, we'll one day reap the benefits of these changes in the form of lower rates of heart disease.

You don't need to be concerned with small amounts of trans fats in beef or dairy products. Naturally occuring trans fats are almost always exempt from labeling rules and other anti-trans-fat initiatives.