This seems to be an area of confusion for many people. Some swear by butter only and others opt for margarine. Who is right? It is time to clear up the confusion.
First of all, both are fats. Therefore, the number of calories in one teaspoon of butter is equal to the number of calories in one teaspoon of margarine. The difference is the type of fat they each contain.
Butter consists of saturated fat. Saturated fat is found mainly in animal products -- meat, milk, cheese, ice cream, lard -- but may also be found in plant products like shortening, coconut oil, and palm oil. The more saturated fat a product contains, the more solid it will be at room temperature. Eating a lot of saturated fat leads to increased cholesterol levels.
Margarine is made of partially hydrogenated vegetable oils. Vegetable oils are unsaturated fats, which are better for our health than saturated ones. The key words to make note of is “partially hydrogenated.” To make the oils solid, hydrogen is added, resulting in a trans fatty acid byproduct. These trans fatty acids have given margarine a bad rap, because they are just as bad for our cholesterol levels as saturated fat.
So what is the solution? Read labels when you are shopping. As of January 2006, all packaged food products must list the amount of trans fats they contain on their nutrition fact panels. If a margarine has no trans fats, it will read "0" on the label. Some products have also added a label that states “no trans fat” or “trans fat free.”
Regardless of which you choose, margarine or butter, you still need to limit the amount you add to foods. One tablespoon of margarine or butter equals approximately 100 calories.