hi sir,my son name is adhrit.he is 4yrs old but not put on weight his weight 12 kg

A. hello mom some individuals even after having a good diet they dont gain weight that very easily , their metabolism is such , so a little varaition is acceptable as far as they are active for their age and eating a healthy diet. give them foods such aa eggs , different type of dals , legumes such as chana , rajma etc stuff paranthas , fresh fruit milk shakes , panner , ghee , soya , sago etc