I agree with you and I think another opinion would be in order,I would feed her full fat foods, whole milk, cheese, good carbs, if you research they do lists of foods that can put weight on .what is her energy like does she play and run ,the diarreha is something should be addressed as something is causing it, could be an allergy .so thats the first thing to get sorted out I am surprised this Doctor thinks that's normal
I try to feed her plenty of healthy foods but she gets her share of junk food too. I don't restrict her diet at all and offer food several times a day. The doctor says some kids are just small and as long as she's growing it's not a problem. But frankly, I just don't believe her. It makes no sense to me that she would be SO small.
What food is she getting ..what does the doctor tell you about her weight .?