We’ve gathered some quick answers to common questions about trans fatty acids — including some tips on how to avoid them.

What are trans fatty acids?

Fatty acids are the building blocks of fat. For example, the fat in olive oil is made up of a variety of fatty acids (e.g. oleic and linoleic). Trans fatty acids have a different shape or structure than other fatty acids. Although a very small number of trans fatty acids occur naturally in animal products, the overwhelming majority of them are formed when manufacturers chemically alter vegetable oil in the process of partial hydrogenation. Because trans fatty acids have a different structure, they also behave differently in the body than other types of fatty acids.

How does trans fat affect the body?

Trans fat has been associated with an increased risk for coronary heart disease. A high intake of trans fat seems to increase both total and LDL (bad) cholesterol levels while lowering HDL (good) cholesterol levels — the exact opposite of your goals for a healthy heart.

What changes should I make?

A panel of the National Academy of Sciences stated that the only safe level of trans fat intake is zero. Since it’s impractical to eliminate all trans fat from our diets, the Academy has recommended that you reduce your intake as much as possible. Recently, manufacturers have been required by law to label foods for trans fat. If a food has less than 0.5 grams of trans fat per serving, they can label it as 0 grams in the Nutrition Facts label. One way to avoid trans fats is to look at the ingredient list on packaged foods and make sure that the words “partially hydrogenated” are not there.

Where are trans fatty acids found?

Foods that have partially hydrogenated oils in the ingredient list typically have the most trans fat. Partially hydrogenated oils are often found in margarines, baked goods, fast food, cookies, crackers, chips, donuts, and many fried foods.

What should I eat instead?

The best advice is to eat a diet made up of whole grains, fruits, vegetables, and legumes (beans and peas). Avoid, or at least reduce, your intake of foods made with partially hydrogenated oils. If you must have margarine, look for the new varieties that are labeled trans fat-free. Try using nut butters or 100% fruit spreads instead of margarine on breads. When baking, use expeller- or cold-pressed oils instead of margarine.