Underweight 19 months old.........

I have a 17 month old .He too is a fussy eater .I tried pediasure for 4 months after he turned one .I gave 220 mls everyday i dont see any change in his weight.I am not sure if pediasure really works.He finished 6 boxes so far hadn't gained even a kilo.So i gave up pediasure ,he is on regular cow milk now.I give milk only in night and early morning i beat 1 whole egg with 80 mls warm egg filter the residues and give in bottle he finishes only if he is asleep .You can try that.I started in Nov though he hasnt put on much wtg atleast he has an egg everyday.He likes eating with us from out plate so I keep away his portion in the plate and feed from that.He is improved on his solid now that he has all his teeth.