Trans Fat Definition

Fats consist of carbon, hydrogen and oxygen and belong to the group of molecules called lipids. These are found naturally in small amounts in certain foods (e.g., dairy products, beef and lamb). Trans fat (also called trans fatty acids) is formed when liquid vegetable oils go through a chemical process called hydrogenation. These trans fats are also called hydrogenated fats and the process of hydrogenation involves adding hydrogen under pressure to make the oils more solid. Hydrogenated vegetable fats are used by food processors because they allow longer shelf-life and give food desirable taste, shape, and texture. Food products made with fats or oils with a high proportion of saturated or trans fatty acids have a longer shelf life than products made with oils that contain a higher proportion of other fatty acids. Saturated and trans fatty acids also play a role in producing the textures and flavours that make many bakery products and snacks so tempting. For example, it is the saturated and trans fatty acids that give pastries that "melt in your mouth" feeling. The US Food and Drug Administration has required that saturated fat and dietary cholesterol be listed on food labels since 1993. Starting January 1st 2006, trans fats must also be listed.

Trans fats and saturated fats are often referred to as bad fats. These fats increase the risk for certain diseases while good fats, meaning monounsaturated and polyunsaturated fats, lower the risk. For a healthy diet replace saturated and trans fats (the bad fats) with polyunsaturated and monounsaturated fats. While unsaturated fats (monounsaturated and polyunsaturated) are beneficial when consumed in moderation, saturated and trans fats are not. Saturated fat and trans fat raise LDL cholesterol levels in the blood. Dietary cholesterol also contributes to heart disease. Therefore, it is advisable to choose foods low in saturated fat, trans fat, and cholesterol as part of a healthful diet.

Although cholesterol is in food the average person makes about 75% of cholesterol in the liver and about 25% is absorbed through food. The fats in your diet have the largest influence on blood cholesterol levels. Although it is still important to limit the amount of cholesterol you eat.

Trans fat and diet

Americans consume on average 4 to 5 times as much saturated fat as trans fat in their diets. Major Food Sources of Trans Fat for American Adults

(Average Daily Trans Fat Intake is 5.8 Grams or 2.6 Percent of Calories)
40% cakes, cookies, crackers, pies, bread, etc.
21% animal products
17% margarine
8% fried potatoes
5% potato chips, corn chips, popcorn
4% household shortening
3% salad dressing
1% breakfast cereal
1% candy

Data based on FDA’s economic analysis for the final trans fatty acid labeling rule, "Trans Fatty Acids in Nutrition Labeling, Nutrient Content Claims, and Health Claims" (July 11, 2003)

Sources of trans fat

The majority of trans fat can be found in shortenings, stick (or hard) margarine, cookies, crackers, snack foods, fried foods (including fried fast food), doughnuts, pastries, baked goods, and other processed foods made with or fried in partially hydrogenated oils. Some trans fat is found naturally in small amounts in various meat and dairy products. Unlike other fats, the majority of trans fat is formed when food manufacturers turn liquid oils into solid fats like shortening and hard margarine.

trans fat in foods - by food category

Baby Food      Baked Products
Beef Products    Breakfast Cereals
Cereal Grains and Pasta    Dairy Products
Drinks    Ethnic Foods
Fast Foods    Fats and Oils
Fish    Fruits
Lamb, Veal, and Game Products    Legumes and Legume Products
Meals, Entrees, and Sidedishes    Nuts
Pork    Poultry Products
Sausages and Luncheon Meats    Snacks
Soups    Spices and Herbs
Sweets    Vegetables
Cakes    Fruit Juices
Soy Products      Sauces
Shellfish      Candy
Spreads      Soda
Dried Fruits      Soups
Cookies      Biscuits


We have sorted our nutrition database by different fat content.

Total fat content in food
Saturated fat content in food
Trans fat content in food
Mono-unsaturated fat content in food
Poly-unsaturated fat content in food
Cholesterol content in food

Excess Trans Fat

Trans fat, like saturated fat and dietary cholesterol, raises the LDL cholesterol that increases your risk for CHD. Excess consumption of saturated fat, trans fat, and dietary cholesterol raises low-density lipoprotein (LDL), or "bad cholesterol," levels, which increases the risk of obesity and coronary heart disease (CHD). Excess fat in the diet because of the high calorie content, can increase your chances of obesity, which increases the risk of heart disease and some types of cancer. Bad fats, ie saturated and trans fats, increase the risk for certain diseases while good fats, meaning monounsaturated and polyunsaturated fats, lower the risk. Although saturated fat is the main dietary culprit that raises LDL, trans fat and dietary cholesterol also contribute significantly. According to the National Heart, Lung, and Blood Institute of the National Institutes of Health, more than 12.5 million Americans have CHD, and more than 500,000 die each year. That makes CHD one of the leading causes of death in the United States.

Recommended allowance of trans fat

The FDA estimates that the average daily intake of trans fat in the U.S. population is about 5.8 grams or 2.6 percent of calories per day for individuals 20 years of age and older.

Related Pages

Tips to lower fat intake can be found here to follow a low fat diet.