Americans are getting pickier about which pack of soda they pick up.

Both Coca-Cola (KO) and PepsiCo (PEP) are seeing a drop in volume sold in North America. For the maker of Coke, volume growth declined 1% last quarter for the region, offset by an 8% increase in prices.

Rival PepsiCo saw its North American beverage volume drop 6%, offset by a 9% increase in prices.

Executives from both companies say they're seeing a resilient, optimistic US consumer — though buying habits are changing for some.

"The [North America] consumer has stayed pretty resilient throughout 2023, in the face of fear," Coca Cola CFO John Murphy told Yahoo Finance over the phone. "Pricing in the course of 2023 was much sharper than it has been for a long time."

Murphy said some shoppers, particularly low- and middle-income consumers, are feeling the pinch as their weekly spending rises. People are making "more value- and cost-conscious choices," he said, including looking for drinks at different pack sizes and price points.

Last quarter, fewer Americans drank water, sports drinks, coffee, and tea, but orange juice and Coke remained popular.

In a similar tone, PepsiCo CEO Ramon Laguarta told Yahoo Finance last week, "We're seeing consumer confidence going stronger in the US and we're seeing consumers feeling better."

Laguarta said he believes PepsiCo has a "competitive advantage in smaller size(s)."

In a recent earnings call, Laguarta partially attributed the slowdown in the company's revenue growth to North American consumers being pressured on the disposable income front, but he remains optimistic.

"We feel good about the fact that we think wages will go higher than inflation next year. And we hope that by the summer, interest rates will go down and that will create another source of oxygen for disposable income in households," he said on the call.

Bank of America has Buy ratings on Coca-Cola and PepsiCo, given they are high-quality, multinational businesses that can generate sustainable returns, analyst Bryan Spillane told Yahoo Finance.

Investors are looking for "sales and volume growth" in the space, and though the two tend to be neck and neck, Coca-Cola sales will likely outpace PepsiCo in 2024, Spillane predicted.

Shares of both are down from a year ago, in contrast to the S&P 500's (^GSPC) nearly 20% rise.

Though the cost of dining out keeps rising — up 5.1% year over year in January per the latest CPI data — Americans are continuing to return to their pre-pandemic habits.