Amazon's cheaper prices at Whole Foods could be leading to longer lines

It seems like Amazon's efforts to get more shoppers through the door at Whole Foods was a success.

According to data provided by Foursquare to Bloomberg, store traffic was up 25% in the two days after the chain lowered prices on select items. Foursquare compiled the data by comparing it to the week prior.

The price changes were much publicized, and in some cases were substantial. Avocados for example, went from $2.50 to $1.50 each, while Fresh Atlantic Salmon Fillets went down a full $5 per pound.

The sharp traffic uptick is a clear message that Amazon knows exactly what customers want, and won't hesitate to throw its weight around to make Whole Foods more competitive in the grocery industry.

It's unclear if Whole Foods will be able to retain these new customers, and if they liked what they saw enough to continue coming back to the store.

"A lot of people went to see what they could see," Bloomberg Intelligence analyst Jennifer Bartashus told Bloomberg. "The question is if they think the prices are low enough to change their shopping behavior - it takes a very long time to change a consumer's perception of prices and value."