I have read some articles saying that the most economical and environmentally friendly animals we can all eat would be grasshoppers and earthworms.

The eating of grasshoppers goes back as far as human history. They are in fact, listed in the Old Testament as one of the foods which is kosher (spiders are not). As far as protein production goes, the average square acre of grass produces more far more grasshopper protein by weight than beef, pork or chicken protein. Grasshoppers are also mostly free of the pathogenic diseases that fellow mammals such as cows and pigs (or whales or dolphins) might suffer from. Some people might scoff and say 'but grasshoppers are grouse looking', however lobsters are a popular food item and they are hardly any more attractive. Also, consider that lobsters eat the fecal matter and decaying corpses of other animals, whereas grasshoppers only eat grass.

A similar case has been made for earthworms. Earthworms are perfectly nutritious, and are said to taste like beef. A square acre of ground also produces more earthworm meat by weight and volume than can could sustain a cow, pig or chicken. Incidentally, the rumor that McDonald's hamburgers are made from earthworm meat has been proven false, since currently a pound (or kilo) of earthworms is more expensive ($30/pound for worms) than a pound of beef. This is due to a greater demand for beef.

One of the reasons behind the Falkland war in the late 1980's was because the tiny Falkland Islands happened to be close to the breeding grounds for Atlantic Krill. Scientists in England had determined that krill was 'the food of the future', that there would be an upcoming food shortage. Thus, securing the Falkland Islands would give Britain access to these shoals of krill which might mean the difference between a national food shortage and a food surplus for trade or sale.