Margarine is a product that was the answer to a substitute for butter, first discovered in France, by Hippolyte Meges-Mouries in response to a challenge by Emperor Napoleon III. The original margarine was made from beef fat. Margarine today is composed of vegetable oils and water. Fats that are liquid at room temperature undergo a hydrogenation process that adds hydrogen to the carbon double bonds in the oil. As the double bonds are broken, hydrogen atoms bond to the carbon atoms. The final result is a product that is higher in melting point than the original oil. This adding of hydrogen to the oil is called "saturated fat."
Sometimes, the hydrogenation process is incomplete, limiting the amount of saturation that actually occurs. Some of the carbon to carbon double bonds remains in the margarine. This is called "trans fats," and has been the subject of study as it relates to coronary artery hardening.
As limiting factors go, the amount of hydrogenation would be the chief determining factor on the amount of margarine produced. The balance between the amount of fat used and water used would also have an effect on the final amount of margarine yield. The type of metal used as a catalyst for the hydrogenation would also be a critical factor. Nickel is traditionally used, but palladium has been substituted as well.