WASHINGTON—Lately, the colorful, chaotic snack aisle at the grocery store has gotten even more cramped. With a deluge of 100-calorie packs of everything from Cheetos to beef jerky, food manufacturers have provided a seemingly healthier alternative to super-sized bags of snacks.

While portion control may help consumers control their cravings, it will also lighten their wallets. According to a survey by the Center for Science in the Public Interest, 100-calorie packs cost, on average, about two-and-a-half times as much per ounce as similar products in larger packages. A comparison of 30 varieties of 100-calorie packs found that the premium charged for those snacks ranges from a modest 16 percent to a whopping 279 percent.

“Hundred-calorie packs are an ingenious way for companies to charge consumers more for less,” said CSPI Executive Director Michael F. Jacobson. “Manufacturers get the best of both worlds—they make more money, and they look like they’re helping people control their weight. But consumers could save money by divvying up their regular box of Cheese Nips themselves if they are worried about downing the whole container. Or better yet, they could skip the junk foods altogether and reach for a piece of fruit.”

Shoppers may not notice the price differences since most varieties of 100-calorie packs are priced similarly to a box of cookies or crackers, at about $3 per box. However, when comparing the prices per ounce, the original items are by far the better value.

For example, a box of Keebler Right Bites Chips Deluxe 100-calorie packs cost $2.50, while a bag of Keebler Chips Deluxe Chocolate Chip Cookies runs $3. But the regular bag weighs four times as much, making the 100-calorie packs three-and-a-half times more expensive per ounce. Similarly, Goldfish 100-calorie packs are triple the cost per ounce of a regular package, and 100-calorie packs of Sun Chips are more than twice as expensive per ounce.

While some 100-calorie packs are new concoctions inspired by traditional snack foods, such as Oreos Thin Crisps, others are simply smaller bags of foods like pretzels, almonds, or graham crackers. According to the July 7, 2007 New York Times, sales of 100-calorie packs reached $200 million annually after just three years on the market.