What does it mean to have natural nails?  Natural nails are those happy, healthy nails with free edges that are not split(vertically) or peeling(layers of the nail lifts).  The most important part of healthy happy nails are the free edges without any problems.  If the free edges are in good condition, polishes has a tendency to last longer.  Polished nails only lasts on natural nails for three to four days at most. 

The fact is that natural nails are not living tissue but do take on water, they expand.  The polish does not expand with the natural nail, therefore, the polish chips or peels.  Gel nails, Shellac(CND), gelcolor(OPI), etc. will react the same way as nail polishes on damaged, peeling, short and split natural nails.

Peeling Nail

Healthy, happy nails

Split Nail