On the one hand, the truck definitely exists. It contains both matter and mass and when you try and pick it up you can feel the force of gravity keeping it anchored to the ground. I even ate food from it one day—bok choy food!—and, at least in theory, my body converted that food into usable energy.
That suggests the truck is real, and also a solid lunch option.
On the other hand, having an entire mobile food operation devoted to a dark leafy green that would likely fall outside of most peoples’ theoretical “My 10 Favorite Dark Leafy Greens” list is way more absurd than anything in Portlandia’s We Can Pickle That! sketch. If Carrie Brownstein and Fred Armisen drove around Portland in an all-bok-choy-all-the-time food truck, convincing knit-beanie-wearing lunchers that kale is dead, that would make for good TV.
That suggests this is actually an elaborate Portlandia sketch. Maybe we’ll never know.