Commodities are not a good investment over the long term because of man's ingenuity in discovering new ways to use existing resources or new technologies to replace depleting ones, according to Dylan Grice, a research analyst at Societe Generale.

Gold Bars

The long-term return on commodities since the 1870s has been zero as "the history of our species has been one of adaptability and innovation, and I argued that to buy commodities was to short human ingenuity," Grice wrote in a market note.