Serious Eats - seriouseats.com

Seyo,
in terms of cost per calorie, fresh food is indeed more expensive in the US. a bag of chips has way more calories than a (bigger) bag of carrots, for example, but it probably costs the same or much less. so purely in terms of energy you'll get out of it, it's much cheaper . . which can be important when you're trying to wring the most out of every cent. but eventually of course it has an impact on health.

Ed,
corn-fed beef might taste better, but it's a pretty indefensible practice nonetheless. in this country, corn-fed usually means industrially-produced, which is a disaster in several ways:

- environmentally, because of pollution from the cows themselves, monoculture and pesticide use on the corn, gas used transporting things all over the country, and a number of other reasons.

- economically. governmental policies are dicatated by agribusiness, and are good only for the companies that process food and sell pesticides and etc - they're not good for any farmers, even the ones who work for them. agribusiness almost completely fails to deal with externalities like pollution and etc, which are not reflected in the cost to the buyer - we pay it through taxes or we leave it for our children to deal with.

- internationally. the industrial growing of corn requires pesticides and etc that are derived from petroleum. it takes something like five barrels of oil, iirc, to produce one slaughter-ready industrial cow. if corn is grown on non-industrial farms, practices like crop rotation eliminate the need for that kind of chemical input. our petroleum use is, to say the least, a factor in a number of worldwide conflicts, not to mention global warming and etc.

but even if you leave all that aside, cows aren't meant to eat corn. their digestive systems aren't equipped to handle it, so for them to survive on that kind of diet and not get sick and die, they have to be pumped full of drugs. antibiotic use on factory farm feedlots is a huge contributer to the development of drug-resistant strains of germs, and if it doesn't stop, someday soon we're going to learn what it was like to live in a world before antibiotics because ours just won't work anymore.

long story short: it might taste better, but it's terrible in virtually every way and is also full of drugs and nastiness. unless you're saying grass-fed is somehow inedible, it has to be the way to go.

(most of this was drawn from Pollan's "The Omnivore's Dilemma," by the way, which i can't recommend highly enough.)