Trans fat is a type of dietary fat. Of all the fats, trans fat is the worst for your health. Too much trans fat in your diet increases your risk for heart disease and other health problems.
Trans fats are made when food makers turn liquid oils into solid fats, like shortening or margarine. Trans fats can be found in many fried, "fast" packaged, or processed foods, including:
- Anything fried and battered
- Shortening and stick margarine
- Cakes, cake mixes, pies, pie crust, and doughnuts
Animal foods, such as red meats and dairy, have small amounts of trans fats. But most trans fats come from processed foods.
How Trans Fats Affect Your Health
Your body does not need or benefit from trans fats. Eating these fats increase your risk for health problems.
Cardiovascular disease risk:
- Trans fats raise your LDL (bad) cholesterol.
- They also lower your HDL (good) cholesterol.
- High LDL along with low HDL levels can cause cholesterol to build up in your arteries (blood vessels). This increases your risk for heart disease and stroke.
Weight gain and diabetes risk:
- Many high-fat foods such as baked goods and fried foods have a lot of trans fat.
- Eating too much trans fat can cause you to gain weight. It may also increase your risk for type 2 diabetes. Staying at a healthy weight can reduce your risk for diabetes, heart disease, and other health problems.
How Much you can eat
Your body does not need trans fat. So you should eat as little as possible.
Here are recommendations from the 2015-2020 Dietary Guidelines for Americans and the American Heart Association:
- You should get no more than 25% to 30% of your daily calories from fats.
- You should limit saturated fat to less than 10% of your daily calories.
- You should limit trans fat to less than 1% of your daily calories. For someone with a 2,000 calorie a day diet, this is about 20 calories or 2 grams per day.
Reading Nutrition Labels
All packaged foods have a nutrition label that includes fat content. Food makers are required to label trans fats on nutrition and some supplement labels. Reading food labels can help you keep track of how much trans fat you eat.
- Check the total fat in 1 serving.
- Look closely at the amount of trans fat in a serving.
- Look for the words "partially hydrogenated" in the ingredient list. It means oils have been turned to solids and trans fats. Manufacturers can show 0 grams of trans fat if there are less than 5 grams per serving; often a small serving size shows 0 grams of trans fat, but it still might be in there. If there are multiple servings in a package, then the whole package may contain several grams of trans fat.
- When tracking trans fat, make sure you count the number of servings you eat in 1 sitting.
- Many fast food restaurants use solid oils with trans fat for frying. Often they provide nutrition information on their menus. If you do not see it posted, ask your server. You also may be able to find it on the restaurant's website.
Trans fats are under review for their health effects. Experts are working to limit the amount of trans fats used in packaged foods and restaurants.
Making Healthy Food Choices
Trans fats are found in many processed and packaged foods. Note that these foods are often low in nutrients and have extra calories from sugar:
- Cookies, pies, cakes, biscuits, sweet rolls, and donuts
- Breads and crackers
- Frozen foods, such as frozen dinners, pizza, ice cream, frozen yogurt, milk shakes, and pudding
- Snack foods
- Fast food
- Solid fats, such as shortening and margarine
- Nondairy creamer
Not all packaged foods have trans fats. It depends on the ingredients that were used. That is why it is important to read labels.
While it is fine to treat yourself to sweets and other high-fat foods once in a while, it is best to avoid food with trans fats completely.
You can cut how much trans fat you eat by substituting healthier foods for less healthy options. Replace foods high in trans and saturated fats with foods that have polyunsaturated and monounsaturated fats. Here is how to get started:
- Use safflower or olive oil instead of butter, shortening, and other solid fats.
- Switch from solid margarine to soft margarine.
- Ask what type of fats foods are cooked in when you eat out at restaurants.
- Avoid fried, packaged, and processed foods.
- Replace meats with skinless chicken or fish a few days a week.
- Replace whole-fat diary with low-fat or nonfat milk, yogurt, and cheese.
Trans fatty acids; Partially hydrogenated oils (PHOs); Cholesterol - trans fats; Hyperlipidemia - trans fats; Atherosclerosis - trans fat; Hardening of the arteries - trans fat; Hypercholesterolemia - trans fat; Coronary artery disease - trans fat; Heart disease - trans fat; Peripheral artery disease - trans fat; PAD - trans fat; Stroke - trans fat; CAD - trans fat; Heart healthy diet - trans fat
Hensrud DD, Heimburger DC. Nutrition's interface with health and disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 202.
Mozaffarian D. Nutrition and cardiovascular and metabolic diseases. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Philadelphia, PA: Elsevier; 2019:chap 49.
US Department of Health and Human Services; Food and Drug Administration. Trans fat. www.fda.gov/food/food-additives-petitions/trans-fat. Updated May 18, 2018. Accessed July 2, 2020.
US Department of Health and Human Services; US Department of Agriculture. 2015 - 2020 Dietary Guidelines for Americans. 8th Edition. health.gov/dietaryguidelines/2015/resources/2015-2020_Dietary_Guidelines.pdf. Updated December 2015. Accessed July 2, 2020.
Review Date 5/26/2020
Updated by: Meagan Bridges, RD, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.