I'm not certain that the age didn't know a thing or two about food - it was the age of empire, and France and England were both well regarded (though naturally France was the leader) for the quality of their food. Apparently George III's reign was about as good as we got for food. They were certainly still in abundance when Darwin was there.
Here's what QI had to say about these delicious giants of their race:
They were first discovered by explorers and sailors in the 16th century. Immediately, people began raving about their unbelievable deliciousness, comparing them variously to chicken, beef, mutton and butter - but only to say how much better tortoise meat was than the very best of the aforementioned. One giant tortoise would feed several men, and both its meat and its fat were perfectly digestible, no matter how much of it you ate.
Oil made from tortoise fat was efficacious against colds, cramps, indigestion and all manner of “distempers.” (It tasted good, too.) The liver was a peerless feast on its own, and the bones were rich with gorgeous marrow. Then there were the eggs - inevitably, they too were the best eggs anyone had ever eaten. Some sailors were reluctant to try tortoise meat because the animal was so amazingly ugly - but one taste, and they were soon converted.