The prescriptions are a small part of a developing untraditional philosophy at St. Christopher's, where Kersten and others are treating hunger as a disease.
And in September, when the hospital opens its Center for the Urban Child to better integrate children's care, that philosophy will become that much more codified, Kersten said.
The facility is the first children's hospital in the region to screen for food insecurity, Kersten said. That's defined as the lack of enough food to live a healthy life.
"But if you screen," said Kersten, "you have to provide something."
Kersten said that St. Christopher's, with the help of the Legal Clinic for the Disabled, has formed a medical-legal partnership that helps patients apply for food stamps at the hospital.
"We're the only medical-legal partnership at a children's hospital in the Mid-Atlantic," said Elizabeth Oquendo, a lawyer with the Legal Clinic for the Disabled, who helps people get food stamps at St. Christopher's. "It's so surprising how incredibly prevalent hunger is in North Philadelphia."
While the city's poverty rate is just under 27 percent, it's more than 40 percent in the area around St. Christopher's, experts say.
Kersten also helped install a WIC office in the hospital. WIC, the federal Special Supplemental Nutrition Program for Women, Infants, and Children, provides food for pregnant and nursing mothers and their children.
Together, food stamps and WIC have long been considered the most efficient programs to combat hunger.
Lately, Kersten has been considering bringing a version of Fare & Square, the nonprofit supermarket in Chester, to St. Christopher's. The only one in America, the store was created by Philabundance, the region's largest antihunger agency.
"It's exciting to use the hospital as the front line against hunger," he said. "The traditional model of medical care hasn't got as much influence as originally thought.
"So, we're trying to help families in ways never done before - helping them directly deal with hunger."
At St. Christopher's, staffers interacting with patients will often ask two questions that, when posed together, are more than 90 percent accurate in determining food insecurity, Oquendo said: "In the last six to 12 months, have you run out of food?" and, "In the last six to 12 months, have you worried that you're not going to have enough food to make it to the end of the month?"
If people answer yes to both, they're considered highly food-insecure, Oquendo said.
It's important to screen for hunger because, after health insurance, it's the most common need St. Christopher's families have, according to Eileen Carroll, Oquendo's colleague.
In a lobby of the hospital recently, people lined up to purchase the food boxes, which were provided by SHARE, the Philadelphia-based food program that distributes discounted food in the area.
"The stock market and U.S. companies are doing well, but people are not," said Jamiliyah Foster, program director for the Foundation for Children. "People are continuing to lose jobs and not find jobs. As a result, there is real hunger here."
Paying for a box of fruit and vegetables, Claire Richardson, 52, the mother of two children in North Philadelphia, said life toughened after she lost her medical-billing job not long ago.
"I never thought about food stamps or cared about anyone on food stamps," Richardson said, "until I needed them."
Like so many who use St. Christopher's clinics, Richardson is distraught about how little she has to feed her children.
"I don't have $50 to my name, and it has to last two weeks," she said. "How the heck does that happen?"