The "diableros" (hand truck hostlers) from Lagunilla market clustered around La Lupita's Ricos Tacos in the rough and tumble barrio of Tepito were not smiling. "Yesterday these cost me six pesos. Today, it's eight. Tomorrow, who knows, ten?" complained Rodrigo Aldama, 28, pointing at the three greasy tacos on his paper plate, "Vitamin T is rich man's food now." Vitamin T, a staple of urban diet here, includes tacos, tostadas, tamales, tortillas, and most any kind of street food concocted from corn.