Tambunan took over the family's nasi padang business from his mother in 2022.Erin Liam/ Business InsiderIszahar Tambunan, 45, left his job in shipbroking to take over his family business in Singapore.The restaurant, Sabar Menanti, has been selling nasi padang since the 1920s.Tambunan says it's difficult to juggle rising costs and rent while maintaining the quality of food.As the lunchtime rush builds, Iszahar Tambunan remains calm.He directs customers to find seats in Sabar Menanti, his two-story Malay restaurant, while ducking behind the counter to serve the restaurant's signature nasi padang.