How to gain the weight of baby

Hello mga mommy. I just had my check up to other OB. She told me na 2weeks or 1week kulang sa timbang ang baby ko if magbase kung ilang weeks na ko which is 30weeks. What marereco niyo po na veggies and fruits na makapagpapalaki ng very light kay baby? OB told me naman po na nothing to worry, atleast malaman lang namin why maliit siya sa kung ilang wks siya. Thank you in advance mga mommy😊