Your favorite grocery items may be shrinking

'Weight out'

Or, to put it another way, the company is receiving more money for the same product. The food industry has a term for the practice: a "weight out."

Frito-Lay said the weight change is no secret, because the bags are clearly marked.

"Due to rising costs for energy, production and distribution, and rather than raising prices, Frito-Lay has slightly reduced some package sizes by one ounce or less," the company said in a statement.

Potato chips are not the only products being downsized. Disposable diapers are, too. Procter & Gamble cut back the number of Pampers diapers in its packages by 13 percent, but dropped prices by only 7 percent. The company cited increased production costs as the reason.

Consumers may find they are spending the same as before at the grocery ... for smaller quantities

But new mother Jordana Schoor said with the cost of her new production, the last thing she needs is less diaper per dollar.

"As a mother, we want to save as much money as we can," said Schoor. "I'd rather spend the money on the child than on the Pampers."

Magical prices and consumer faith

Analysts say larger and more powerful retailers such as Wal-Mart that market products at lower prices -- and consumers themselves, who have become accustomed to certain prices during the past few years -- contribute to the downsized products.

"Remember, there's a certain consistency of pricing and certain price points that are considered magical, that a lot of companies don't want to violate," said Jaine Mehring of Salomon Smith Barney. "And so, within limits, this is a way to keep those price points intact."

But consumer advocates say the companies risk tarnishing their brands.

"If deceptiveness breaks faith with the consumer, they may lose that customer," said Carol Tucker Foreman of the Consumer Federation Association. "It may be the most expensive ounce of potato chips that Lay's didn't sell."