What Does Pale Stool In A Toddler Indicate?

My baby is now 2 yrs old.she is having the problem of pale stool from last 7-8 months.every month she has pale stool with hard to normal consistency 1-3 times per day for few days then again normal.in these days she remains anorexic.some times undigested food perticles also seen in her poop.her wt is 13 kgs and 200 gm which is absolutely ok with her age.but this problem is continueing.i could not get whether any specific food is making her stool pale or she has problem in digestion or what?please help me