Updated February 11, 2008

Trans Fat Begone!

Julie Lichty Balay, M.S., R.D.

Avoiding trans fats
The average American consumes approximately 5–8 grams of trans fat per day, or 45–72 calories' worth, accounting for about 2% to 3% of total calories consumed per day. Most dietary trans fat is man-made through the hydrogenation process. However, small amounts of trans fat are produced naturally by the bacteria found in the stomachs of ruminant animals such as cows and sheep, so there are trace amounts of trans fat found in dairy products, beef, and lamb. However natural trans fat makes up only about 0.5% of the calories in the average American diet, and natural trans fat is bound to other important nutrients such calcium and iron. Avoiding the man-made variety, therefore, will likely have a greater positive effect on health.

There remains the question as to how much, if any, trans fat is safe to eat. The current consensus among the experts is that man-made trans fat should be avoided entirely if possible.

Avoiding trans fat got easier as of January 1, 2006, when rules took effect requiring food manufacturers to list trans fat separately on the Nutrition Facts panel required on the label of all packaged goods. However, just reading the Nutrition Facts panel may not be good enough to get all the trans fat out of your diet. If the amount of trans fat in one serving of food is 0.5 grams or less, the manufacturer is allowed to state on the label that it contains 0 grams of trans fat. You might think that 0.5 grams is too scant an amount to do any harm, but if more than one serving of the food is consumed over the course of the day, or if several foods containing small amounts of trans fat are eaten, it's easy to consume several grams of trans fat in a day, and, as mentioned earlier, it only takes a few grams a day to have negative health effects.

There is another way to identify foods containing trans fat and that's to read the ingredients list and look for any type of hydrogenated vegetable oil in the list. (See "Detecting Trans Fat" for a visual clue.) Any partially hydrogenated vegetable oil contains trans fat.

As you read labels, you will probably find that some of your favorite foods contain trans fat. Most varieties of peanut butter, for example, are labeled as having 0 grams of trans fat, but they also list partially hydrogenated vegetable oil in the ingredients list. This can be a disappointing experience, but fortunately, due to the new labeling laws and public awareness about trans fat, many manufacturers have either reformulated many of their products or developed new “trans-fat-free” ones. So you should be able to find substitutes for the packaged goods you enjoy. Margarines are a very common source of dietary trans fat, but there are now margarines made without partially hydrogenated oils that are widely available. They are more expensive than regular margarine, but they are worth it if you use such spreads regularly. If you have no choice but to buy margarine that contains partially hydrogenated oil, choose the tub or squeeze-bottle variety rather than stick margarine. The softer the margarine, the less trans fat it has. (Hydrogenation makes oils hard, so softer products have undergone less hydrogenation.)

Eating out is tricky when it comes to trans fat. Unless you specifically ask what type of oil is used for frying (and get an accurate answer), you cannot be sure of the presence of trans fat. Hopefully, there will be a similar trend for restaurants to remove the hydrogenated oil from their recipes the way manufacturers of packaged food have begun to do. However, until there is a ban on trans fats (some European countries and New York City have implemented one!), diners must be aware of which restaurant foods commonly have them and avoid those foods.

Julie Lichty Balay is a nutrition consultant and educator in the New York City area.

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