Dietary control can help reduce the intake of fat, but for significant weight reduction, exercise is the more important preventative. It is the only way to prevent or decrease visceral fat as well.
Believe it or not, (some!) subcutaneous fat is good. Fat shields excess heat, cold, and force like falling off a bike. It also keeps organs in place, insulates the body, and helps regulate hormone levels. It's when subcutaneous fat starts to accumulate in globs and rolls that it becomes an issue - both cosmetic (no, you won't fit in your jeans) and physical.