Environmental concern is a little like dieting or paying off credit-card debt - an episodically terrific idea that burns brightly and then seems to fade when we realize there's a reason we need to diet or pay down our debt. The reason is that it's really really hard and too many of us in too many spheres of life choose the easy over the hard.
Food - I love nuts. I eat them all the time they're easy to carry around and I am never hungry all day long.