The "bad” fats are saturated and trans fats.

Saturated:  Saturated fats occur naturally in many foods.  The majority we eat come mainly from animal sources, meat and dairy (milk fat) such as fatty beef, lamb, pork, poultry with skin, beef fat (tallow), lard and cream, butter, cheese, and other dairy products made from whole or reduced-fat (2%) milk.  These foods also contain cholesterol.  Many baked goods and fried foods can also contain high levels of saturated fats. Some plant foods, such as palm oil, palm kernel oil, and coconut oil, also contain primarily saturated fats, but do not contain cholesterol.

Trans:  Trans fats are found in many foods.  About 20–25 percent come from animal fat and 75–80 percent come from partially hydrogenated fat – especially in commercial baked goods (pastries, biscuits, muffins, cakes, pie crusts, doughnuts and cookies) and fried foods (French fries, fried chicken, breaded chicken nuggets and breaded fish), snack foods (popcorn, crackers), and other foods made with partially hydrogenated vegetable oils, traditional vegetable shortening or stick margarine.  (Soft margarines typically contain very low levels of trans fats.) 

The "bad” fats are saturated and trans fats.

Saturated:  Saturated fats occur naturally in many foods.  The majority we eat come mainly from animal sources, meat and dairy (milk fat) such as fatty beef, lamb, pork, poultry with skin, beef fat (tallow), lard and cream, butter, cheese, and other dairy products made from whole or reduced-fat (2%) milk.  These foods also contain cholesterol.  Many baked goods and fried foods can also contain high levels of saturated fats. Some plant foods, such as palm oil, palm kernel oil, and coconut oil, also contain primarily saturated fats, but do not contain cholesterol.

Trans:  Trans fats are found in many foods.  About 20–25 percent come from animal fat and 75–80 percent come from partially hydrogenated fat – especially in commercial baked goods (pastries, biscuits, muffins, cakes, pie crusts, doughnuts and cookies) and fried foods (French fries, fried chicken, breaded chicken nuggets and breaded fish), snack foods (popcorn, crackers), and other foods made with partially hydrogenated vegetable oils, traditional vegetable shortening or stick margarine.  (Soft margarines typically contain very low levels of trans fats.) 

Americans generally eat four to five times as much saturated fats as trans fats. 

For good health, limit your consumption of saturated fats to less than 7 percent of your daily calories and trans fats to less than 1 percent of your daily calories.

They should both be minimized in the diet. 

Both trans fats and saturated fats increase your bad cholesterol levels and your risk of heart disease.  However, since trans fats may also decrease your HDL (“good”) cholesterol (and may have other harmful effects), some experts believe that trans fats may be somewhat worse for you than saturated fats.  That doesn’t mean you should eat more saturated fats, or that you should substitute saturated fats for trans fats. 

The American Heart Association recommends an overall healthy diet and lifestyle to combat heart disease, with individuals eating less than 7 percent of total daily calories as saturated fats and less than 1 percent as trans fats.  In practical terms, this means eating a diet containing a variety of fruits, vegetables, and grain products, especially whole grains; fat-free and low-fat dairy products; legumes, poultry, and lean meats; and eat fish, preferably oily fish, at least twice a week.

Very small amounts of trans fats occur naturally in some meat and dairy products, so eliminating trans fats to zero is impractical.  We recommend limiting the amount of trans fats you eat to less than 1 percent of your total daily calories. 

For example, if you eat 2,000 calories a day, that means less than 20 calories (less than 2 grams) of trans fats a day – and that’s a very small amount.  For practical purposes, this means avoiding foods which contain or are prepared with partially hydrogenated vegetable oils.

No.  Trans fats are produced in a manufacturing process in which hydrogen is added to make liquid vegetable oils more stable.  Cooking and frying in the kitchen does not create trans fats.  

The type of trans fats that are created by hydrogenation (to harden fats) are not formed during frying, even if the oil temperature is high enough to reach the smoke point. 

At any rate, oil should not be allowed to reach the smoke point because the fatty acids break down easily to form chemical compounds known as oxidation products.  These compounds not only make the oil smell bad and the fried food taste bad, but it is well known that people should not eat foods that have high amounts of oxidation products. 

The chemical structures of the fatty acids change at high temperatures because portions of the fatty acid chains break off to form the oxidation products that create the off-odors and off-flavors. 

Hydrogenation is the process by which liquid vegetable oil is turned into solid fat. 

Partially hydrogenated oils contain trans fats.  However, when liquid vegetable oil is fully hydrogenated, almost no trans fats remain. 

Full hydrogenation increases the amount of saturated fats, mostly in the form of stearic acid.  Stearic acid does not raise levels of LDL (“bad”) cholesterol.  This makes fully hydrogenated fats less harmful than partially hydrogenated fats.

Trans fats, including CLA, occur naturally in beef, lamb, and full fat dairy products.  

Studies suggest that CLA may not have the same negative effects on blood cholesterol that partially hydrogenated oils do, although the other trans fats in meat do.  However, these foods are high in saturated fats and consumption should be minimized. 

The American Heart Association recommends eating less than 1 percent of your calories from trans fats from all sources.

Stearic acid is a saturated fat that is very stable in storage and during frying. 

Stearic acid is used to form margarines, shortenings, spreads, and as a cream base for baked products.  Even though stearic acid is a saturated fat, studies have suggested that it has little effect on blood cholesterol levels.

Interesterified fats are fatty acids that have been chemically or enzymatically rearranged to alter their texture and/or nutritional profile.

In 2007, a study was published with the conclusion that interesterified fats and trans fats have similar health effects in that they negatively alter the metabolism of lipoproteins and glucose.  That study is largely responsible for the recent negative publicity regarding interesterified fats.  

Given the small study sample, the American Heart Association maintains that the safety profile of interesterified oils and shortenings is not as well understood as that of natural fats and oils.  Therefore, additional studies are needed.

Cocoa butter is a natural, yellowish-white vegetable fat extracted from cocoa beans. Cocoa butter is solid at room temperature and very stable.  It is used to add smoothness and flavor in some foods, including chocolate. 

Cocoa butter has significant amounts of saturated fats, but a main fatty acid is stearic acid which has been shown in studies not to raise blood cholesterol levels like other saturated fats.  However, foods containing cocoa butter can be high in calories as well as butterfat and sugar; therefore you should consider them as treats that you eat only once in a while.

People get cholesterol in two ways – the liver produces varying amounts and many foods contain dietary cholesterol. 

Typically, the body makes all the cholesterol it needs, so people don’t need to consume it.  Although saturated fats and trans fats are the main “culprits” that can raise blood cholesterol, dietary cholesterol also plays a part in many people.  The American Heart Association suggests healthy people consume less than 300 milligrams of dietary cholesterol daily – people with heart disease should limit it to less than 200 milligrams daily.

Commonly eaten cholesterol containing foods include eggs, shellfish, organ meats such as liver and whole milk.

Call (800) 242-8721 or e-mail inquiries@heart.org.