my premature twins are 1 and half years old today. when were gaining weight as a normal child till their 10 month. then they got severe viral dysentery after recovered from that they had been suffering from constipation. they are prickly eaters. although they are active, they are now just 8 kg and too thin. their diet as compared to their diet of 10 month old is reduced a lot. please guide how to help them gain weight again.