My 2yr old baby has lack of appetite..ive been giving him multivitamins and vitamins c everyday but seems not working what should i do?

Feeding expectations: A 2yo is an age where they begin to demand independence in frustrating ways & the change in their growth needs puts parents in a bind. Between 2-3 they will grow 2-3 in/4lb compared to 10in/14lb the first year. They seldom if ever eat a balanced meal & i expect them to eat well 3-4d/mo. The rest they just nibble.I expect a balanced wk & most get it. If the kid's growth is ok @ checkups, ok to relax.