The body fat decreases smoothly and evenly. However, following a route that is approximately as follows-retro peritoneal fat abdominal subcutaneous fat Subcutaneous fat femoral. It means that adipose tissue that occurs more active to lose is what is in the gut, thus seem that until there is diminished in that area of the body, not significantly eliminated in other areas of the body.
This is approximate, because the body takes fat from all over, and will have much faster at their disposal, which is more metabolically active. Arms exercises no decrease localized adipose tissue in that area specifically. Yes, tone muscle and improves appearance giving a better shape to the arm, but are reduced locally.
Thus, the exercise you do has to be aerobic, because it uses large muscle groups that consume a lot of calories, such as brisk walking, skiing, running, rowing, skating, cycling, etc. It is advisable that only those physical exercises can burn a total of 2500 calories per week.