what is the margarine metabolism in our body?
As pointed to by @Chris the Wikipedia link for margarine explains that these are formulated upon vegetable oil-based fats. Their melting points and other properties are adjusted by industrial hydrogenation of the unsaturated fatty acids in the vegetable oil. 

Most unsaturated fatty acids present in nature are in the cis conformation at the double bonds. The hydrogenation process, if it is not carried to completion, produces the trans isomers of fatty acids. These so-called trans-fats are blamed for the undesirable side effects of consuming margarine, or other foods containing hydrogenated oils.

Most of the fatty acids present in margarine (i.e. cis unsaturated and saturated fatty acids) are metabolised by the normal route (&beta; oxidation).