Dollar General, Saks’s Off 5th and Chipotle Mexican Grill are among the discounters and fast-food chains set to expand in 2010 as US consumers embrace a “new frugality,” according to Colliers International.

Low-cost restaurants and retailers, including Papa John’s International Inc. and TJX Cos., are planning to add stores following the loss of more than 4 million U.S. jobs last year and a reduction in consumer spending, Boston-based Colliers said today in its 2010 “Retail Trends & Opportunities” report.

“The ‘New Frugality’ is here for at least five years,” Garrick Brown, national retail research director for Colliers, said in the report. “Necessity and off-price retailers will continue to fare best.”