On Wednesday, Deutsche Bank announced plans to restructure its commodities ETFs, the PowerShares DB Commodity Index Tracking Fund (NYSEArca: DBC) and PowerShares DB Agriculture Fund (NYSEArca: DBA).

We covered the story here.

The move wasn't that surprising. After all, when the CFTC revoked DB's position limits back in August, it was really just a matter of time before the two funds either got a makeover or shut down entirely.

But DB's restructuring plans are more than just a new coat of lipstick. The revisions, slated to take effect between Oct. 19 and 31, will significantly change the commodities exposure these funds can give investors.

DBA and DBC, currently worth $2.2 billion and $3.3 billion, respectively, are two of the most popular commodities ETFs. With their high concentrations in just a few key contracts, the funds are ideal for gaining exposure to the Big Guns of the commodity markets.

DBA, for example, tracks the world's staple crops—corn, wheat and soybeans—as well as everyone's favorite additive, sugar. DBC, on the other hand, tracks two staple crops (corn and wheat), two crucial energy sources (WTI crude and heating oil), the most widely used industrial metal (aluminum) and a universally beloved safe haven, gold.

Basically, the old versions of DBA and DBC cover only the A-List commodities, the ones with the highest liquidity and rock-solid, diversified demand pictures.

New-vintage DBA and DBC, however, will incorporate commodities with a little more volatility and a little less liquidity into their composition. DBA will halve its four core agricultural positions to make room for coffee, cocoa and livestock futures, while energy-heavy DBC will drop its current 35 percent weighting in WTI crude to just 12.4 percent, adding in contracts for gasoline, Brent crude and natural gas. (See the full weightings here.)

It's not like DB is dipping into something as illiquid as lumber or uranium here. And by diversifying the portfolio, they lessen the impact of a massive swing in one of the bigger commodity contracts.

But adding in these new markets also has the potential to pump more volatility into the mix, and potentially very different returns. We've all been paying attention to what's going on in natural gas lately, right? And what about livestock? It’s been on a straight path downward for more than two years now.

Even the impact on something like Brent crude will be interesting: Brent is a popular European contract, but it's by no means as widely traded as WTI crude. (By my count, this is the first time a major commodity ETF has invested in a non-U.S. energy contract. The first, but probably not the last.)

In short: DBA and DBC won't look much like themselves anymore. They’ll look more like the more diversified commodity ETFs that are already on the market, such as the iPath Dow Jones-UBS Commodity Index Total Return ETN (NYSEArca: DJP) and iShares S&P GSCI Commodity Indexed Trust (NYSEArca: GSG).

Of course, from the fund's perspective, any weighting overhaul is better than liquidation, and as the CFTC crackdown continues, I'm sure we'll see many more funds try similar alchemy in the future.

But the change is not without consequences. Investors are losing a degree of choice in the commodities market, forfeiting the option of investing only in the biggest of big commodities. And by making a foray into more narrow contracts, DBA and DBC may be potentially exposing investors to added volatility—or at least a very different pattern of returns—as well.