Since the advent of potent anti-HIV therapy there have been increasing reports of changes in body composition among people living with HIV. These include increases in fat in various areas of the body (the stomach area, behind the base of the neck and/or breast enlargement) or decreases in body fat (in the face, arms, and/or legs) and changes in the way the body processes fats (called lipids). Any combination of these conditions is called lipodystrophy. While all these conditions have been lumped together, it's likely they are actually different syndromes which are caused by different things.