"It depends how much corn, how much wheat, how much dairy is available in the world. It comes from everywhere, and it's being sold everywhere, so these days you have to look at overall worldwide demand and there's 7 billion people to feed," he says.

Unfortunately, many shoppers have already experienced increased prices at the grocery store, says Stephanie Nelson, founder of CouponMom.com.

"The manufacturers have figured out some clever ways to increase their revenue without shocking consumers," says Nelson. "In the last year I've seen packaging getting smaller and manufacturers demanding that consumers buy greater quantities in order to receive a break in price."

According to Nelson, many brand-name yogurts used to come in eight-ounce packages, now most of the containers contain six ounces, with some dropping to five ounces. 

"Five ounces? I'd have to eat three of those!" she says.