I actually felt bad for the high-profile food-blog overseer who was recently photographed apparently contemplating eating crap at an airport. The awful truth is that no one (except maybe Saint Alice) is immune to the siren song of garbage for either instant gratification or self-abasement. I would add “simple satisfaction,” but fast food never provides that, as I realized after giving it up on losing 20 pounds in the only upside of my little incident four years ago. Consider this depressing tale: I was walking toward the Greenmarket on 14th Street and thinking about how easy it has been to keep that weight off because I would never succumb to the Taco Bell on my route these days.  After filling my Cuba bag with corn and milk and other weighty stuff, I set off in search of lunch, thinking of the tuna sandwich at The New French 1.24 Mapquest miles away, which would be the perfect stomach liner for a birthday party at 7 that night. I got as far as Seventh Avenue and knew it was beyond me, waited awhile for a bus, then panicked about time and headed toward the C train and a cobbled-together lunch at home. Unfortunately, between me and the 23d Street station the new Qdoba lurked. I figured if I was going to fall off the food wagon, I might as well do it big time, so I ordered vegetarian nachos and was rewarded with a pile of chips in what looked like a pie pan, drizzled with “3-cheese queso,” slopped with pinto beans and green sauce and topped off with “lite” sour cream. I can’t remember the last time I tasted anything that delivered so little of anything you expect from food, starting with flavor. It reminded me yet again why people eat fast crap: They keep stuffing it in and hoping at some point their taste buds will perceive something, anything. No wonder the guy at the high table closest to me was either sleeping or passed out. The saddest part was doing the numbers. Killer tuna on pizza bianca with kick-McDonald’s-ass fries at The New French: $9.50. Bleak shit on a disposable shingle: $7. My colon wants its processing time back.