Holberg lived modestly and was able to invest a large part of the profits from the sale of his books on the side and lend them out or invest them in more active ventures. Several times in his writings he criticized townspeople and nobles who used their resources in unproductive ways to be carried round in chairs, to live in lavish houses and waste money on luxury. He ate reasonably and did not use his money on being driven around. He said that his travelling on foot, and continued walking, was the reason he could keep his malaria, which had plagued him in the south, under control.