Here are some calories/dollar calculations (and you can verify them using the links below): 1. Ground Beef - $3.725 per lb (in June 2016, according to the BLS

Here are some calories/dollar calculations (and you can verify them using the links below): 1. Ground Beef - $3.725 per lb (in June 2016, according to the BLS[1]) - 971 calories per lb [2] - 260 calories per dollar 2. Lettuce - $2.029 per lb (also from the BLS, same link as above) - 77 calories per lb [3] - 38 calories per dollar 3. Apples - $1.444 per lb (also from the BLS, same link as above) - 235 calories per lb [4] - 162 calories per dollar The math doesn't lie. Lettuce is almost an order of magnitude more expensive per calorie than ground beef. And you can go look up other fruits or leafy green vegetables (I used two of the examples you provided), they basically all fall in this range. Some meats (mostly seafood) are more expensive per calorie than beef, some are less expensive (mostly poultry and pork). What it all boils down to, though, is that if you want to feed more people with the same amount of land/energy/whatever, you need to be looking at dairy (500-800 calories/$), oils (1200-2000 calories/$), and especially grains (> 2000 calories/$). There's a reason why the dawn of civilization coincided with agriculture and domestication of grains: grains are an incredibly cheap source of calories. Also, FYI, in the U.S. at least, organic food is not usually pesticide free. It just means that only "natural" pesticides are used. And harvesting things by hand is terrible for the environment. Humans are incredibly expensive and use tons of resources. After all, human generally want things like cars, climate controlled dwellings, and latest gizmos and gadgets, whereas a tractor could care less about these things :P. [1]: http://www.bls.gov/regions/mid-atlantic/data/averageretailfoodandenergyprices_usandnortheast_table.htm http://www.bls.gov/regions/mid-atlantic/data/averageretailfo... [2]: http://nutritiondata.self.com/facts/beef-products/6197/2 http://nutritiondata.self.com/facts/beef-products/6197/2 [3]: http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2475/2 http://nutritiondata.self.com/facts/vegetables-and-vegetable... [4]: http://nutritiondata.self.com/facts/fruits-and-fruit-juices/1809/5 http://nutritiondata.self.com/facts/fruits-and-fruit-juices/...