Fat in the diet does not necessarly translate into fat on the body, overall calorie intake also needs to be considered, although some types of fats are more readily stored as bodyfat than others.
Trans fats are the ones to avoid. Hydrogenated vegtable oils are vegtable oils which are usually liquid at room temperatures, they change the structure with hydrogen which makes the unsaturated bonds saturated and produces a fat which is solid/speadable at room temp then use it instead of traditional fats like butter, lard,tallow and shortning.
A quick search on askjeaves threw up the following:
Trans-Fats
Also indexed as: Hydrogenated Oils, Hydrogenated Vegetable Oils, Margarine, Partially-Hydrogenated Oils, Vegetable Shortening
Like butter, margarine is often used as a spread; when cooking with margarine, do not heat it to high temperatures.
Trans fats are produced through hydrogenation, a chemical process by which hydrogen is added to unsaturated fatty acids. Hydrogenation converts the unsaturated bonds in the oil into saturated bonds, creating a solid, spreadable fat with increased shelf life. Hydrogenation gets rid of some double bonds, but incompletely transforms others. These double bonds are transformed from the natural “cis� configuration to the “trans� configuration. Research indicates that eating trans fats is associated with an increased risk for heart disease.
Varieties
Margarine
Margarine was developed in the late 1800s as an inexpensive alternative to butter. Typically margarine is made from one or more partially hydrogenated vegetable oils (
soy, corn,
sunflower, or safflower), but it may also contain animal fats.
Packaged baked goods, crackers and chips
Most processed foods contain partially hydrogenated soybean,
coconut, or palm oil.
Vegetable shortening
Vegetable shortening is created by the complete hydrogenation of vegetable oil. Because the hydrogenation process is complete, the shortening contains very few trans fats.
Buying and storing tips
A variety of margarines are available. They include hard, soft, liquid, whipped, salted, unsalted, and diet. Soft margarines are not fully hydrogenated and contain fewer trans fats. Margarine can be stored in the refrigerator or freezer. To prevent it form absorbing food odors, make sure that the container is sealed or that the margarine is well wrapped. Store vegetable shortening in sealed container in a cool, dry place.
Availability
Margarine and vegetable shortening are available in most grocery stores and some natural food stores.
Preparation, uses and tips
Like butter, margarine is used as a spread. In addition, margarine can replace butter in cooking and baking. Margarine should not be heated to high temperatures.
Nutritional Highlights
Margarine, 1 tsp margarine (5g) (hydrogenated, corn oil)
Calories: 34
Protein: 0.04g
Carbohydrate: 0.04g
Total Fat: 3.8g
Fiber: 0.0g
Health benefits and concerns
Atherosclerosis
Among the most important dietary changes in protecting arteries from atherosclerosis is avoiding foods that contain trans fatty acids (margarine, some vegetable oil and many processed foods containing vegetable oil). Increasingly, the importance of avoiding trans fatty acids is being accepted by the scientific community. Leading researchers have recently begun to view the evidence linking trans fatty acids to markers for
heart disease as “unequivocal.�
High cholesterol
Trans fatty acids (TFAs) are found in processed foods containing partially hydrogenated oil. The highest levels occur in margarine. Margarine consumption is linked to increased risk of unfavorable changes in cholesterol levels and heart disease. Therefore, margarine and other processed foods containing partially hydrogenated oil should be avoided.
High homocysteine
People with high homocysteine levels are typically advised to reduce their consumption of processed foods, meat, and saturated fats, because these dietary changes lower the risk of heart disease.
Preeclampsia
Data from one preliminary trial suggest diets high in trans fatty acids are associated with an increased risk of preeclampsia. Trans fatty acids are found in partially hydrogenated vegetable oil, such as margarine.
Ulcerative colitis (UC)
In one study, people with a high intake of animal fat and cholesterol had a four-fold increase in risk of UC, compared with people who consumed lower amounts of these fats. Another study found that ingestion of certain high-fat foods (particularly margarine) was associated with increased risk of UC. Although these associations do not prove cause-and-effect, reducing one’s intake of animal fats is often recommended as a means of improving overall health.
Health benefits and concerns for fats and oils
Many health benefits and concerns associated with this food are applicable to other fats and oils. Read about
health benefits and concerns for fats and oils for a full description.