Starbucks Corp said on Thursday it would expand its  loyalty rewards program at grocery stores to include more products, as it seeks to win more customers amid a soft retail and restaurant environment in the United States.

The coffee chain's move to more than triple the number of products it sells under the rewards program comes following customer backlash after Starbucks overhauled an existing program last year.

Companies have been tweaking their rewards programs in recent years to make them less-generous to consumers.

Seattle-based Starbucks, which launched its rewards program in 2009, made changes to it last year, which irked some customers and caused a furor on social media.

Under the changes, customers earn two "stars" for every $1 spent and need 125 stars to get a free food or drink item, which meant that some customers would have to spend more money to get free items.

Customers earlier used to receive one star per purchase and could redeem 12 stars for an item.

Starbucks said on Thursday its U.S. customers could now earn stars on a wider range of products, sold mainly at grocery stores, including its K-Cup packs, packaged roast & ground coffee and multi-serve chilled coffee.

The move from the world's biggest coffee chain also comes after its warning last month that full-year revenue growth would be at the lower end of a previously forecast range amid stalling growth in its U.S. business.