Over the past couple of years, I have worked to avoid trans fats. Although food manufacturers are now required to label the amount of trans fats in the foods, some still get away with using small amounts. Anywhere you see "partially hydrogenated..." you can bet that there are trans fats in the foods. I guess the FDA allows them to say "0 g" if it is below a certain amount.
More recently, I have begun efforts to also avoid foods with high fructose corn syrup (which I will abbreviate as "HFCS"). An article by Kim Severson from sfgate.com describes the history of HFCS and how, as our food became inundated with this ingredient in the 1980's, there was a strong, correlating rise in obesity. Also, the article describes studies to suggest that HFCS interacts with hormones, including insulin, leptin and ghrelin, in a way that may lead to weight gain. Some argue that HFCS itself has not led to obesity; rather, they suggest that the overconsumption of foods with all types of refined sugars is the cause.
I suspect that HFCS is added to many foods because it is cheaper than making a product with genuine, high-quality flavor. Instead of enjoying real fruit flavor in a yogurt, we taste the sweetness of HFCS with some artificial and small amounts of real fruit flavor. And we like sweet. Instead, though, why not use plain yogurt and add some non-sweetened fruit spread? I've also found that a small pinch of brown sugar, which is maybe 15-20 calories and far less than the amount used in regular yogurt, does the job just fine if I want something a little sweeter. (Would you add a dab of HFCS to your yogurt?) I've noticed that the less sweetness (from refined sugars) I have in my food, the more I learn to taste the natural and subtle flavors of the food.
I also suspect that HFCS is added to some foods that would normally be less sweet, just so that people are more inclined to eat more of them (and, therefore, buy more of them). I don't have any hard evidence of this, but the drive to make profits and to help people eat in moderation do not go hand-in-hand.
Along with my efforts to avoid trans fats and to eat more "whole foods"--foods that don't come pre-packaged or which have recognizable ingredients listed--I will also try to cut out any foods with HFCS. Actually, I think I'll try to cut back on all refined sugars. We'll see how it goes!