Butter vs Margarine?

This is probably one of the most common misconceptions out there regarding food and nutrition.  Which is better--butter or margarine?  Let me explain.

Butter is a source of naturally occurring saturated fat.  It is made from cow's milk and is made from cream.  Very fatty, but delicious.  To simplify,  eating too much saturated fat can lead to clogged arteries, which can increase one's risk of developing cardiovascular problems, such as coronary artery disease, or high cholesterol.

Margarine is available in a variety of options.  They are all made from vegetable oils, which is liquid at room temperature.  In order to solidify the oil to mimic the texture of butter, a process called hydrogenation needs to occur.   This process means chemically changing the molecule by adding hydrogen atoms.  Unfortunately, hydrogenation creates "trans fats", which also have long term consequences on heart health, such as clogging arteries.

Now which option is better?

The best choice would be an unhydrogenated margarine, where this process of hydrogenation does not occur and there would be no trans fats in the product.  An example would be Becel, or Earth Balance.
I find that Earth Balance tastes incredibly similar to butter, and is a 100% vegan formula.  Also works well for baking recipes.