Contrary to what I suspect was your intent, you aren't being clever. You're just reinforcing the point that every choice has consequences...some intended, some not. For instance, the net increase in CO2 from your "cycle to work" respiration would, I suspect, be less damaging than the total net consequences of building, maintaining and driving a car. It'd be cheaper, too. Eating more greens might well make you fart more, though that's less than certain, but it would surely be less than the methane produced by the beef cattle that less-healthy eaters consume so voluminously.

Perhaps with some expansion, your reply could have made a serious contribution. Instead, it comes off looking glib.