A heating system for warming nutritional liquid fed to a neonate or preterm infant may comprise a control module and a heater. The heating system is portable so that the heating system is not connected to a syringe pump or other device used to feed the neonate. The heater of the heating system is mounted to the tube that is used to feed the neonate. The heater is positioned along the tube in close proximity to the neonate so that a temperature drop of the nutritional liquid after the nutritional liquid exits the heater and reaches the neonate is negligible. The heater raises the temperature of the nutritional liquid to a target desired temperature (e.g., body temperature of the mother and neonate or to a temperature above the temperature of the mother and neonate) so that the neonate may consume warm nutritional fluid. Once the nutritional liquid reaches the neonate, the nutritional liquid is at about the body temperature of the mother or neonate or at least above room temperature.