We know that there are 3 major food groups: carbohydrates, proteins, and fats. Among these three, fat is the major source of energy for the body, since one gram of fat can provide 9 calories, as compared to one gram of carbohydrates or proteins, which can only provide 4 calories.  Fat makes intestinal absorption of Vitamins A, D, E, K, and carotenoids possible. I bet everyone agrees that fat in the diet also provides taste and consistency of food and makes us feel full. However, we should be aware of the established risks that are associated with fats. As you will see, not all fats are commendable.

It used to be that fats occur only either as saturated or unsaturated fats. Saturated fats have adequate hydrogens and they usually occur in solid form at room temperature. Unsaturated fats, on the other hand, have missing hydrogens in their structure, so instead of solidifying at room temperature, they occur in liquid oil. [1]

Back in 1901, a German chemist named Wilhelm Normann showed that hydrogens could be added to liquid oils (unsaturated fats) turning them into sticky margarines (saturated fats) through a process called hydrogenation.  His discovery made it possible for whale oils and fish oils before to be stabilized for longer periods. The fat industry realized that by turning liquid oils into solid form, for instance, turning soybean oil into margarine, allowed them to store more oils for a considerable period of time. [2] It was also found that due to its chemical features, margarine, unlike butter, can be taken out of the refrigerator. Margarine also tend to be more spreadable on breads. Furthermore, hydrogenated fat provided superior baking properties than lard.

Today, these chemically altered hydrogenated fats are known as “trans fat”. Trans fats are manufactured commercially and can be found in vegetable shortening, some crackers, margarines, snack foods, baked products such as doughnuts and pastries, and foods made with or fried in partially hydrogenated oils like fried chicken and french dried potatoes. [3] They are neither essential nor beneficial to one’s health. In fact, scientists have found out that consumption of trans fat (including saturated fats and dietary cholesterol) can build up “bad cholesterol” or low-density lipoprotein (LDL) in the body, increasing the risk for cardiovascular diseases.

Starting last January 1, 2006, food manufacturers are required by FDA to include trans fat content on their food labels, in addition to the saturated fats and cholesterol content. With trans fat added to the Nutrition Facts panel (usually listed under the line of saturated fat), consumers would know how much of all three—saturated, cholesterol and trans fats—are in the foods they choose.

Here are some helpful tips you can keep in mind to make sure that saturated fat, cholesterol and trans fat are maintained low in the diet.

1)  When comparing food products, look at the Nutrition Facts panel, and choose
the food with the lower amounts of saturated fat, cholesterol and trans fat. In
choosing foods low in saturated fat and cholesterol, the general rule of thumb is:
5% of the daily value or less is low, while 20% or more is high. [3] So far, there is
still no recommended percent daily value established by the FDA on trans fat.
[2]. If the amounts of fat in the product are provided (saturated,
monounsaturated, polyunsaturated), compare the total with the total fat on the
label. If they don’t agree and you notice that partially hydrogenated oil is listed
in the ingredients, the difference is most likely trans fat content.

Also, watch out for claims on packages quoting “low or no cholesterol”.
Saturated fats may be minimal in these products, but the trans fat is still present.

2)  Use monounsaturated or polyunsaturated fats found in olive and canola oils,
soybean oil, corn oil, sunflower oil and foods like nuts. [3] These fats do not raise
the “bad cholesterol”.
3)    Avoid solid shortenings, hard margarines, and animal fats, including butter. Use liquid vegetable oils (except coconut and palm kernel oils) instead.
4)  Prefer fish (mackerel, sardines, salmon) instead of meat. These contain         omega-3 fatty acids, and are low in saturated fats. [4]
5)  If meat is inevitable in the diet, choose lean meats such as poultry without the skin and lean beef and pork. All of which should not be fried. [3]
6)  Foods high in cholesterol (eggyolk, liver, full-fat dairy products) should be limited in the diet. [3]
To view some common foods that were tested for trans fat, please visit this website: http://cspinet.org/nah/septrans.html
Now that nutritional food contents are already provided in Nutrition Facts panel, as responsible consumers, it is imperative for us to know how to understand them. This information can help us a lot in choosing the right foods that we should eat, in order to avoid the risk of acquiring diseases that are preventable in the first place.

References:
1) Megan Tupa. Trans Fat: What is it? Where does it come from? And why haven’t we heard anything about it? http://www.vanderbilt.edu/AnS/psychology/health_psychology/Transfat.htm
2) Trans fat. http://en.wikipedia.org/wiki/Trans_fat
3) Revealing Trans Fat. FDA Consumer magazine Pub No. FDA05-1329C. http://www.fda.gov/fdac/features/2003/503_fats.html
4) Fish and Omega-3 Fatty Acids
http://www.americanheart.org/presenter.jhtml?identifier=4632