Science marches on... but is it always for the good? Developed in the 1940s, hydrogenated oil in processed foods -- especially baked goods -- became widely present in the 1970s as a preservative. The problem is, we have now come to realize the impact the manipulation of nature has had on our bodies. Trans fats (more correctly, trans fatty acids, also called partially hydrogenated oils), increase LDL ("bad") cholesterol, decrease HDL ("good") cholesterol and put people at increased risk for diabetes. So much for progress.

The good news is that starting in January 2006, the food industry must list the presence and amount of trans fats in foods on nutrition labels. With 40% of foods on supermarket shelves containing trans fats, savvy food manufacturers are scrambling to remove them from their products, rather than having to list them. But it is proving to be a real challenge, and in the search to find a replacement for the versatile trans fats, some manufacturers are rumored to be returning to the use of saturated fats, including highly saturated palm oil, which are notorious for increasing artery-clogging blood cholesterol and consequent heart disease.

What's your best strategy for staying healthy in this trans-ition? Nutrition educator Liz Marr, MS, RD, past president of the Colorado Dietetic Association and co-owner of a food and nutrition communication firm, Marr Barr Communications. Marr is pleased about the government mandate to label trans fats, in part, she says, because it is forcing manufacturers to reduce trans fats where they can. However, she cautions that consumers must remain vigilant about paying attention to nutrition labels. Processed foods will continue to have some form of fat -- the issue is to determine what kind and how much you are getting.

The standard recommendation concerning fats is to eat 30% of your daily calories in fats and in equal amounts of saturated, polyunsaturated and monounsaturated fats.

To be sure your fat consumption is at its best, Marr advises searching out all fats on the food labels -- especially trans fats and saturated fats -- and monitoring how much and what types of fat you consume. Saturated and trans fats are marginally okay (passable if that's your only food choice) if they are at the end of a long list of ingredients, which means that they have negligible presence in the food. Polyunsaturated or monounsaturated fats are good so long as you stay within the recommended number of calories to maintain a healthy weight. Of course, your best bet is to eat fats from whole foods rather than processed foods. Cook with healthy oils, such as olive oil or canola oil. And, eat foods rich in essential fatty acids, such as nuts, seeds and fresh fish.