It's not "poisoning" but...
[warning: this may be considered uncouth, but it should be discussed! I will keep my terminology as mild as possible...]
... I have to watch out for places that use new-fangled "diet" or "healthier" cooking oils, grill sprays, etc. Otherwise in 15-30 minutes I've got the 'trots' and am driving home really fast (with explosive results) - can't even sit and enjoy my newspaper & coffee after dinner at some of these places.
I'm soured on fast food in general because you feel "bleah" after eating it. But Wendy's, Jack-in-the-Box and others seem to put this greased lightning in their sauces, etc. Some salad dressings seem to trigger same response too: my mom said some dressings may have some mineral oil in them!!!
I am not 'ill' from this (i.e., not nauseated, etc.) - just 'drained'. Probably does wonders for keeping the weight off as food doesn't stay in long enough to have its nutrients absorbed.
I avoid some of this by having my breakfasts
(I eat breakfast a lot, even at dinner) cooked on 'dry grills' - meaning that they don't use grill spray or they'll use a tiny dollop of butter. That really seems to stop the problem.
I have a cast-iron gut and can eat stuff deep friend in Crisco, but this new stuff - with palm oils, canola, etc. triggers some sort of what must be an allergic reaction. These new cooking oils, etc also seem to be cheaper, according to a restaurant mgr I know.
In high-priced (labor, real estate, etc.) Kalifornia this seems to occur frequently. But when I was in eastern Oregon or Reno this wasn't a problem - and I ate out constantly there. We ate quite frequently at a Flying J truck stop and I had no problems at all. (Flying J food is pretty good, too, given the venue.)
I don't think this is a unique problem, and I do think it is increasing: visit a restroom now in these restaurants using the cheap oils/ sprays, and you're likely to see evidence of prior 'blowouts' in their restrooms. I don't recall seeing nearly as much of this a decade ago!
There may be a genetic component to this too... my mom & dad could eat breakfast at our local diner, whereas I'd be running out 15 min later unless I specifically ordered it cooked on a 'dry grill' - which means having the grill scraped down of residue. Seems that even a tad of this gives me the trots.
As for your Subway experiences: would you trust a place that sells *round*, perfectly formed roast beef? Thank you, I'll find a Safeway deli. About the same price, real food, and they use gloves in preparation.
Bill Wiese
San Mateo, CA