Originally Published: 14 FEB 23 13:22 ET

By Parija Kavilanz, CNN

(CNN) -- Get ready for heartbreak in the candy aisle.

As Valentine's Day arrives, so does the annual frenzy to buy or gift the classic Russell Stover and Whitman's Sampler chocolate boxes that come in under $12 or so at Walgreens, CVS, Walmart and Target stores.

But shoppers may be disappointed this year when they open those big red or pink heart-shaped boxes, according to one consumer advocate. That's because the packaging is misleading, said Edgar Dworsky, a former assistant attorney general in Massachusetts, who is editor of the website ConsumerWorld.org.

There's sometimes precious little candy inside, he said.

Dworsky said his research shows the over-sized boxes deceive consumers into believing there's more chocolate inside when there isn't.

Consumer watchdogs have a name for the tactic, called "slack-fill," and it's not allowed under federal law. Regulators judge whether a product is slack-filled by comparing the capacity of the package to the amount of product it actually contains, he said. Then they determine if the extra space in it is nonfunctional and doesn't serve a legitimate purpose, like protecting the product.

This is different from the "shrinkflation" phenomenon, a product packaging practice that's typically triggered when inflation surges and companies' costs go up. To contain those costs, companies put products in packaging that appear smaller, lighter in weight and decorated with less flashy colors.

Dworsky said a reader alerted him to the chocolate boxes a few days ago and sent him evidence of a heart-shaped Whitman's chocolate sampler box.

The box, 9.3-inches wide and 10-inches high, had a net weight of 5.1 ounces. "That's a pretty decent size," said Dworsky. But when the box was opened, it had 11 pieces of chocolate inside.

So, Dworsky bought a few of this year's Whitman's boxes (priced at $7.99 each) and removed all of the inside packaging material and inserts. "The chocolate pieces only filled up one-third of the box."

Dworsky didn't have evidence that brands are actually skimping on the chocolates compared to previous years. But CNN found one Russell Stover heart-shaped candy box -- with a Best Before date of June 10, 2006 and kept as a memento by one of our staffers -- of the same size, 9 inches wide by 10 inches high.

It featured 24 pieces.

Dworsky also found a 5.1 ounce Russell Stover heart with nine pieces of chocolate inside. "It's almost double the size of the 4-ounce Russell Stover box, which has seven pieces," he said.

"Imagine being the recipient of the bigger box. If you're giving it to your love on Valentine's Day, they think it's decent-sized big box of chocolate but then it only has nine pieces in it," he said. "It's awful."

Both brands do disclose on their boxes the weight and the approximate number of candy pieces inside. Swiss chocolate company Lindt & Sprüngli, which owns Russell Stover, Whitman's and Ghirardelli brands, referred requests for comment to Russell Stover Chocolates.

Russell Stover Chocolates said it "works to clearly indicate to our customers what is included in our packaging."

"This includes sharing the product weight and how many pieces are in all of our Valentine's Day boxed chocolates," said Patrick Khattak, the brand's vice president of marketing, in an email to CNN Business.

Regulators have gone after chocolate makers in the past over so-called deception packaging. California district attorneys filed a lawsuit in 2019 against Russell Stover and Ghirardelli for allegedly using false bottoms and other deceptive tactics in some chocolate boxes and bags, making the packaging look more filled than it really was.

Prosecutors also accused Ghirardelli of using less cocoa in their products than advertised.

The DAs, which included the Santa Cruz District Attorney, settled the case and the companies paid a fine of $750,000 without admitting any wrongdoing, but agreed to make packaging changes.

Edward Browne, an Assistant District Attorney in Santa Cruz, said he will be looking into this recent example of potentially deceptive packaging by the companies. He said Dworsky had reached about to him about his most report looking at the Russell Stover and Whitman's chocolate candy boxes.

"It's unfortunate that this situation is still going on. It's also disappointing," Browne told CNN. "We will take a look and see if the companies are taking advantage of any exceptions to the law. There have been many exceptions added since our case in 2019 and they eat up the rule."