Here's evidence of consumer pain lurking beneath the surface of this economic recovery

Since the financial crisis, most sectors of the US economy have dramatically improved.

But there are still sore spots.

In a recent research report to clients, a team of Credit Suisse analysts led by Robert Moskow shared a chart showing that food stamps issued as a percent of total food purchased in the US skyrocketed to over 12% from less than 6% after the financial crisis.

And while that number has dipped slightly to around 10% in 2015, it is still far away from pre-crisis levels.

"Record participation in the 'SNAP' program (formerly called 'food stamps') is evidence of just how stressed the core consumer really is," the analysts noted in the report.

Credit Suisse

On the retail side of things, the fact that lower income consumers have not kept pace with the economic recovery has hurt processed food brands and businesses.

"Business can't be good for brands like Chef Boyardee when its core consumer is under-employed and dramatically changing its shopping behavior," write the analysts. "Their core consumer is shopping less often and reducing her transaction size per trip."

Still, the bigger theme here is that it looks like lower income consumers have been feeling a squeeze since the financial crisis - even with basic things like food.