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Megan Tupa

Index - click on a topic

What is trans fat?

How did the process of trans fat come about?

Where is trans fat found in my diet?

How may the consumption of trans fat affect my health?

Are there alternatives to trans fatty acids?

Why is trans fat a secret fat?



As we enter into the latter third of the 1990's, many Americans would characterize the growing interst in health, fitness, and nutrition as a trend of the decade. More Americans than ever before have shown concern over their cholesterol level, joined an exercise facility, or been caught in the grocery store examining the label on a food product. If all this is true, then why do we hear on the news and read in magazines that Americans are heavier than ever before?

A few years ago, the Food and Drug Administration (FDA) began requiring that food companies label products with the percentage of the daily value of carbohydrates, proteins, fats, sodium, and certain vitamins as well as the standard amount per serving in grams. This new regulation has not only given consumers more information about the make up of food products but has contributed to America's heightened nutritional awareness. As each of us read over these labels, it has probably crossed your mind, as it often does mine, is this information really accurate? How can a piece of chocolate cake have only one gram of fat and taste like "the real thing"? A french bread pizza with pepperoni, only five grams of fat, is that possible?

Some companies may reveal information about monosaturated fat, and polyunsaturated fat, but they are only required to list saturated fat as well as total fat content. While most consumers look only for a product's total fat content, a more knowledgeable shopper may also examine the amount of saturated fat a product contains. Only the most observant consumer may notice that the amount of unsaturated and saturated fats on the label often times do not add up to equal the total amount of fat. How is that possible? What is this excess fat? Trans fat. A man made substance which researchers suggest may be as bad for your health as saturated fat. Because food companies are not required to list trans fat on product labels, its quiet existence may be potentially worse. Could trans fat be the secret which is keeping health conscious Americans from losing weight?

What is trans fat?

In order to understand the nature of and secret behind trans fat, it is necessary to explain what fatty acids are. Fatty acids can be described as chains of carbon which are able to combine with other molecules. These acid chains vary in length and may be either saturated or unsaturated. Saturated fatty acids have adequate hydrogens and therefore a straight configuration which allow them to pack into a solid crystal at ambient temperatures. On the other hand, unsaturated fatty acids are missing adequate hydrogens, so rather than solidifying at ambient temperatures, a liquid oil is produced. Unsaturated fatty acids are labeled either monounsaturated or polyunsaturated depending upon the number of hydrogens which are missing. Polyunsaturated fatty acids lack the greatest number of hydrogens making it the most unstable. Trans fat is monounsaturated or polyunsaturated fat which is altered by partial hydrogenation. This process of partial hydrogenation forces the oils which are naturally liquid at room temperature to become solid, therefore modifying the fat so it is more similar to saturated fat. While trans fatty acids are considered unsaturated by chemical definition, the transformation is so severe that trans fat can not be legally labeled as monounsaturated or polyunsaturated fat on packages.

How did the process of trans fat come about?

The hydrogenation of vegetable oils began in the United States in 1910. Shortly afterwards, crisco went on the market as a replacement for lard. In the 1950's, the growing fast food industry as well as the baking and snack food industry, began to capitalize on the ability to turn liquid oils into solid fats. The hydrogenation process is controlled by a number of factors including room temperature, pressure, duration, and source of fats. Partial hydrogenation of fats and oils results in a mixture of fatty acids. As the degree of hydrogenation increases, the proportion of polyunsaturates decreases, monounsaturates and trans fatty acids increase, and saturated fats increase slightly. The FDA informally defines a hydrogenated fat as one that is solid at room temperature. Such fats typically contain 15-20% trans fatty acids whereas partially hydrogenated oils are liquid at room temperature and are lower in trans fatty acids.

Where is trans fat found in my diet?

As mentioned earlier, the development of crisco in the early 1900's was the onset of hydrogenated cooking and vegetable oils. Today, these oils still maintain a good amount of trans fat as a result of the man induced hydrogenation process. Other foods which are major contributors to trans fatty acid intake are baked goods such as doughnuts and pastry, deep fried foods such as fried chicken and french fried potatoes, and imitation cheese. Snack chips, cookies, and crackers often contasin high amounts of trans fat as well. Trans fat can also be found in some natural sources including milk, sheep, goats, deer, buffalo, and marsupials. These sources have been found to have significantly lower levels of trans fatty acids than those which are a result of manual hydrogenation. For a detailed list of many commonly eaten foods which have a significant amount of trans fat, click HERE.


How may the consumption of trans fat effect my health?

Although not much research has been done on the effects of trans fat in relation to health concerns, research has correlated trans fat intake with heart disease, diabetes, cancer, low birth weight, obesity, and immune dysfunction. It is to be noted that nearly all of these claims suggest that further research be done in the area. Much of the discrepancy contends that research has not been able to differentiate whether these trends are a result of saturate fat or trans fatty acid. For example, those people who discontinue the use of butter and replace it with margerine, have lowered their intake of saturated fat but increased trans fat intake. Not enough research has been done to differentiate between the two and draw significant conclusions.

Another notable concern suggests that trans fatty acids disrupt cellular functioning and therefore may effect enzymes such as delta-6 desaturase which may in turn interfere with the conversion of omega-6 and omega-3 essentail fatty acids resulting in future deficiency of these acids.

Are there alternatives to trans fatty acids?

Of course there are alternatives, doesn't everything today seem to have an alternative? It should be mentioned that trans fat is not bad in moderation, it is excessive intake which will more than likely be the cause of problems. It has been suggested that vegetable oils are best consumed when in their natural, unhydrogenated form, for example olive and sesame oils. The processed oil industry has argued that trans fatty acids only replace solid, saturated fats, but this is not necessarily true. Also, it has been shown that margerines and shortenings can be made without trans fatty acids. There appear to be many ways to avoid trans fatty acids, the healthiest would require individual changes in eating styles, but to do so, we must have the help of the producers.

Why is trans fat considered to be a secret fat?

For starters, it can be assumed that not many people have even heard about trans fat, at least in comparison to other saturated and unsaturated fats. This fatty acid is an essential part of the diet which not much is known about. It is critical for those trying to lose weight to understand this fat because replacing saturated fats unknowingly with trans fat could result in weight gain concurrent with what the American population is presently experiencing.

On the other hand, the FDA requires that saturated fat be labeled on food products and limits the extent to which they can label their items as low cholesterol. But without labeling trans fat, a company is able to label their product cholesterol free when in reality, the product may contain a substantial amount of cholesteral by means of trans fat. Click HERE for more information on what food labels don't tell you.



Overall, strong arguments are being made by researchers and nutritionists nationally for the labeling of trans fat on food products. This labeling of food would at least improve the ability of the consumer to make appropriate choices. It should be reiterated though, that simply knowing the secret behind trans fat will not do the trick. It takes change and maintenance of a healthy diet and lifestyle to lose weight and narrow one's risk of disease.


Anonymous. Position Paper on Trans Fatty Acids. American Journal of Clinical Nutrition, 1996, 63, 663-70.

Ascherio, A. & Willett, W. Trans Fatty Acids: Are the Effects Only Marginal? American Journal of Public Health, 1994, 84, 722-4.

Beardsley, T. Trans Fat: Does Margerine Really Lower Cholesterol? Scientific American, 1991, 264, 34.

Chen, Z., Cunnane, S., Fortier, L., Ratnayake, W., & Ross, R. Similar Distribution of Trans Fatty Acid Isomers in Partially Hydrogenated Vegetable Oils and Adipose Tissues of Canadians. Canadian Journal of Physiology and Pharmacology, 1995, 73, 718-23.

Dupont, J., Feldman, E., White, P. Saturated and Hydrogenated Fats in Food in Relation to Health. Journal of the American College of Nutrition, 1994, 75, 190-2.

Hornstra, G. & Mensink, R. Alternatives for Nutritional Trans Fatty Acids. World Review of Nutrition & Dietetics, 1994, 75, 190-2.

Hornstra, G. & Von Houwelingen, A. Trans Fatty Acid in Early Human Development. World Review of Nutrition and Dietetics, 1994, 75, 175-8.

Jones, D. Trans Fatty Acids and Dieting. Lancet, 1993, 24, 1093.

Marckmann, P. Trans Fatty Acid and Dieting. Lancet, 1993, 24, 1094.


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