Transcript for The Incredible Shrinking Grocery Products

Next tonight "World news" investigates something happening in grocery stores across America. Your favorite foods shh rinking inside the packaging with the price saying the same. Rebecca Jarvis gives you answers on how to spot it. Reporter: Just as the appetites of Kristin Quinn's children are starting to grow. You want apple yogurt? Reporter: She's finding less product for the old price. This is not something that would ever come on my radar Reporter: Edgar at consumer world has spent his career tracking products and shh rinking packaging. Take a look at these two boxes of crackers. They cost the same but take a look inside the new box. It has 20 fewer crackers. How about the juice boxes. The new one 10% less juice. So we have lost one of those ten boxes in the new package. Reporter: It's not just food. You go through a lot of these. Yes. Reporter: Thinks large pack of Pampers used to hold 100 diapers and now to 92 even though it's still $26 a pack. Kristin will be spending $200 more on diapers before her baby is potty trained and look what's flushing away before our eyes. Ladies you can't squeeze the Charmin. Reporter: 70% less to squeeze than 20 years ago. And remember the old brand. The new is less than four. Reporter: Another thing offmay not notice at the grocery store, they're bigger bags next to the smaller version. What's the difference between these two? The new one, almost two ounces less. Reporter: So do some checking before you hit the checkout. We reached out to the manufacturers who told us when their costs rise, they adjust the packages. Remember the cookies. Here they are. Hard to tell which one is the bigger package and smaller one. This is the smaller package. It's the newer one. Six fewer cookies and that weight is where you find that answer. You have to become an expert on the weight. On the weight. Thank you so much. Eye-opening as always. When we come back our

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