Margarine

Margarine is a generic term used to indicate any of a wide range of butter substitutes. In many parts of the world, margarine is now the best selling table spread, although butter and olive oil also command large market shares. It is used as an ingredient in the preparation of many other foods. Margarine is commonly called butter in informal speech, but (at least in the United States) food packaging is not permitted to refer to margarine as "butter". Recipes sometimes refer to margarine as oleo (see below) or shortening.

Conventional margarine contains a much higher proportion of so-called trans fats than does butter. Because research shows a correlation between diets high in trans fats and coronary heart disease, margarine has come to be perceived by many as unhealthy. Others argue that margarine remains healthier than butter, because butter's higher saturated fat content poses a greater hazard than margarine's trans fats. In response to trans fat concerns and government demands for labelling, margarine manufacturers are making and selling new varieties that contain less or no trans fat. In particular, tub margarine is sometimes lower in trans fat than stick margarine, but tub margarine is usually too soft to be suitable for baking.

Although many Americans are told margarine contains less saturated fat than butter, it is not exactly true it is healthier per se. As mentioned above, trans fat is used in the process of solidifying margarine to look like butter. If a margarine does contain high concentrations of trans fats, then it is actually worse than butter. This is because in addition to raising LDL ("bad cholesterol") like saturated fats, it actually lowers HDL ("good cholesterol"). An easy rule of thumb to judge healthiness of oils is simply the fluidity. Saturated fats are usually solid and bad for your health, while liquids are better. Margarine is better if liquid and unsolidified.