McDonald's is losing ground to rivals like Burger King with a key customer group

Low-income diners are spending less at McDonald's, Numerator found. Mario Tama/Getty Images McDonald's is losing sales among low-income diners, new data shows. Numerator found that sales among low-income customers slipped 2.4% duing the chain's latest quarter. McDonald's has said that the execution of its latest value menu hampered second-quarter sales. McDonald's is losing ground to rivals among low-income fast-food diners, according to recent data. Spending by low-income guests at the…