This study investigated the printability of a typical food ternary (starch-lipid-protein) gel system and revealed the critical role of protein. The results revealed that a higher content of α-helix and a lower content of random coil in proteins positively impacted the printing accuracy of the ternary gel system. Higher α-helix content in proteins increased the shear rate at the nozzle, ensuring smooth extrusion during 3D printing while also reducing the gel velocity and filament expansion, which led to smoother filament surfaces. Moreover, higher α-helix content and lower random coil content in proteins increased V-type crystalline structures, average molecular size (R