But not everyone puts their newfound knowledge to use. Bruce Cook, a 61-year-old veteran, also took part in the program in Corpus Christi. Recently, after he picked up power greens and carrots from the diabetes pantry, he returned the next day, grabbing a dozen chocolate-chip-and-M&M cookies at the regular pantry.

“I know what I’m supposed to eat and not supposed to eat,” he said. “But I still eat what I want.”

Sadly, food banks are ideal places to reach patients with uncontrolled diabetes. What used to be temporary assistance has become a lasting fixture in many lives, especially among older adults and the unemployed. Some have access to medical care, but few doctors ask if patients can afford food.

“The choices you make depend on the choices you have, and often in health care we forget to ask about the choices people have,” said Dr. Robert L. Ferrer, the vice chairman of research in the department of family and community medicine at the University of Texas Health Science Center in San Antonio.

After two-thirds of Dr. Ferrer’s patients told him they ran out of money for food every month, he began a study with the San Antonio Food Bank for patients with Type 2 diabetes to see if handing out provisions and healthy recipes in his office parking lot might help.

But for many with low incomes, the challenges never end.

Three months into the Houston program, Ms. Lathon had lost 20 pounds, and her blood sugar was dropping. But she needed emergency surgery to remove her appendix, and then suffered severe burns on her arm when a pot of boiling water overturned at a crawfish festival.

Her blood sugar has risen significantly, as is often the case when people with diabetes experience stress or illness. And she has finished the experimental diabetes program at the Houston Food Bank.

She isn’t sure what’s next.

“I loved that nutritious program; that’s what kept me going,” she said.