More Americans are buying groceries on credit. Here’s why that’s a problem.

The issue of affordability has become political fodder, kicked back and forth like a soccer ball in a World Cup match.

But this is no game for struggling Americans. The latest Urban Institute survey on family well-being and basic needs highlights a critical shift in consumer behavior. Last year, more than 1 in 3 working-age adults used credit cards to buy groceries — and many of them had trouble paying them off.