The city of Tiburon, California (the name mean “shark” in Spanish) banned them from all restaurants. The Chicago City Council is trying to do the same in “the city that works.” Health advocates try to get them thrown off all elementary and secondary school menus.

       Are trans fats really that bad for you? The short answer is, "Yes!" Partially hydrogenated or hydrogenised oils are ubiquitous in packaged and processed foods. They give cake toppings their “luscious smoothness and moisture,” and let baked goods stay on store shelves months and years. From an epidemiologic standpoint, they appear to clog arteries and increase stroke and heart attack rates more than saturated fats.

       But it pays to know history. How did we get to this state of affairs? Courtesy of Pamela Hartman Cohen in the most recent “Harvard Public Health Review,” here is a brief history of trans fats:

• Approximately 9,000 years ago: Trans fats hit the human diet in a small way. People start regularly eating milk and dairy products produced by newly domesticated goats, sheep and cows.
• 1903: The first industrial patent of trans fats is granted. Over the next 100 years their use grows exponentially. Processed with trans fats, foods are kept palatable for years and are easily be transported. With time, trans fat products like Crisco become cheap.
• Mid-1950’s: University of Minnesota epidemiologist Ancel Keys starts publishing studies of varied European populations showing that saturated fats cause cardiovascular disease, the leading killer in America.
• 1985: Harvard Researcher Frank Sacks points out that beef fat is used everywhere to fry fast foods. As meat-based saturated fats are now vilified, the outcry provokes many fast food chains to shift to trans fats.
• 1980’s–1998: The government-backed program to move Americans to low fat diets increases the backlash against red meat and saturated fats. Plant-based trans fats are used, especially in baked goods, to fill in the gap.
• 1990: Researchers show that trans fats decrease HDL (good) cholesterol, while increasing LDL (bad) cholesterol by major amounts.
• 1994: Walter Willett and others publish reports that trans fats are more damaging to the heart than saturated fats. Attempts to regulate trans fats are put down by the FDA. However, Unilever starts taking trans fats out of its products.
• 2003: Frito Lay and other corporate giants move away from trans fats.
• 2004: Evidence accumulates that trans fats increase bodily inflammation. Studies argue they cause immediate spasm and dysregulation of arterial walls.
• 2005: The Department of Agriculture creates a new series of food pyramids. Specific recommendations to avoid trans fats are left out. It’s an old story. Something once regarded as normal and good, namely red meat, is demonized because of its saturated fat content. It’s frequent replacement, trans fats, turns out to be worse. As of this year, the law is that American food manufacturers must list trans fats on product labels.

       Except they don’t.

       It may be the law, but it’s another thing to enforce it. Food labels rarely mentioned the term “trans fats.” What you will read on the box is “partially hydrogenised soybean oil,” or, “partially hydrogenated palm oil.”

       Assuming you look at the labels. Most people don’t. If they did, they would realize that many of their meals come from oil barrels and are produced in industrial processes that look a lot more like petrochemical cracking than anything normally associated with food. Trans fats were developed to make foods cheaper, tastier, more appetizing, long-lived. A hundred years ago probably no one thought they would harm health.

       We know they hurt survival now. People often think that while cholesterol and saturated fat laden steaks and hamburgers may be “bad,” crackers, cakes and baked goods can’t be as harmful. They’re wrong. Look for partially hydrogenised or hydrogenated oils on the package and you may find out part of the truth.

       Ingesting a tiny bit of trans fats probably won’t kill you. But eating a lot of them will help kill tens of thousands of Americans each year. Don’t expect your restaurant owners to change. Often they don’t know the nutritional effects of many of the additives, preservatives and sauces they use. You have to protect yourself. You can stick to whole foods, making unprocessed plant foods the mainstay of your diet.

       It also pays to read the labels. Food and drugs are much closer than people think. More than we want to know, we are what we eat.

Dr. Matthew Edlund, M.D., M.O.H., director of The Center for Circadian Medicine, is an expert on applied public health, sleep medicine and psychiatry. A former professor at Brown and University of Texas medical schools, he can be reached via email to DocME@DoctorEdlund.com. And CLICK HERE to subscribe to our new Fitcast, via the iTunes Store.