What's So Bad About Trans Fats?

When New York City banned trans fats from restaurants in 2006, it shined a spotlight on these dangerous fats. Although there are some trans fats that occur naturally (and that you don’t have to worry about), most trans fats (the ones you should avoid) are formed by taking unsaturated fats — which are fluid at room temperature — and turning them into solid fats through processing. This is done by adding hydrogen to the fat in a process known as partial hydrogenation.

What Do They Do?
Trans fats are particularly pernicious to your health because they raise your bad LDL cholesterol and also lower your good HDL cholesterol. (Saturated fats — the kind trans fats are trying to mimic — raise both your LDL and HDL.) That takes a toll on your heart. Just a few extra grams of trans fat a day (about 4 grams in a 2,000-calorie diet) can increase your risk of heart disease by 23 percent!

How to Avoid Them
Eating minimally processed whole foods is the best way to avoid trans fats. And when you are buying processed foods, check the labels. On most packaged food labels, there’s now a line for trans fat. Looking for items with 0 grams of trans fat is a start, but it’s not enough. Labeling laws allow food manufacturers to claim “0 grams of trans fat” if the item has less than a 1/2 gram of trans fat per serving. And that adds up if you eat multiple servings. To truly avoid trans fats, you need to read the ingredient list. If you see the words “partially hydrogenated,” the product contains trans fat. And by the way, regulation works — a 2012 study published in the Annals of Internal Medicine found that New Yorkers have dropped their intake of trans fats without increasing the amount of saturated fats they eat since the law went into effect.

Kerri-Ann is a registered dietitian who writes on food and health trends. Find more of her work at kerriannjennings.com or follow her on Twitter @kerriannrd or Facebook.