Despite Q2 earnings per share that beat analysts expectations, Whole Foods investors should be worried about an even more critical sales figure.

While total sales increased by a meager 1.3%, transactions at the green grocer fell 2.1%, and that’s a much more telling metric, Business Insider reports.

Transactions are a direct measure of foot traffic, and while Whole Foods’ 3% drop in same-store sales can be attributed to price cuts, there’s no good way to explain a drop in traffic other than a loss of customers.

The transaction drop is a clear sign Whole Foods is losing customers. The primary reason, according to analysts, is that its prices are still too high when compared to its competitors—especially with low-cost foreign chains like Aldi swooping in.

That could change, though, as Whole Foods just unveiled its new low-cost "365" stores in an effort to capture customers in a changing retail landscape.[BI]