This pattern of weight loss deserves further investigation. Speak again with the pediatrician and tell him/her you want to know what options are available. Perhaps he will be seen by an endocrinologist. To lose one quarter of his weight is a cause for concern.
ok and what if you have seen a dr for it and they said he is just fine.
Request a second opinion.
My granddaughter is also losing weight despite a concerted effort to increase her caloric intake (half and half in her cereal, ensure, etc.). Doctor will run a fast blood sugar so diabetes is a possible diagnosis, What are some other differential diagnoses for which we should be testing? There are a lot of autoimmune diseases on both sides of the family. Any suggestion areas to rule out would be helpful.