"When I eat and I see my mom and dad don't, I say, 'Why don't you eat?' " he said. "It makes me feel nervous and kind of sad and stuff.
"I worry about them. I try to give them my chicken nuggets."
Marcus Sr. gently turns down his son's offers and tells him not to fret. "As long as you guys eat, we're OK," he said he tells the boy. "Me and Mommy will find something."
As hard times get harder, they seem to press more unyieldingly on the poor.
"The whole life of someone economically stressed is a lot more fragile than before," said Bill Clark, executive director of Philabundance, the region's largest hunger-relief agency.
The agency has seen need in the Philadelphia area grow 22 percent over last year, and 66 percent since 2009.
For the poor, the increase in food prices means they must spend an extra $30 a month, a huge sum for low-income people, analysts say.
"I never thought I'd be where I am," said Mary Reed, 48, a married mother of two in Bellmawr, Camden County. Reed cares for an 8-year-old autistic son, and her 60-year-old husband was laid off from a warehouse job in 2008. She must frequent food pantries to get by. "I never thought we'd hit rock bottom like we did," she said.
While suffering is local, some global factors are causing food prices to rise, according to Ricky Volpe, a retail food specialist at the U.S. Department of Agriculture.
First, prices of commodities - staple crops such as wheat and corn - are up, according to Steve Reed, an economist with the information and analysis branch of the federal Bureau of Labor Statistics. Similarly, the price of fuel used to ship food is up.
Prices of grain have risen because there is more demand for it throughout the world, said Elaine Waxman, vice president for research of Feeding America, the nation's leading hunger-relief agency, of which Philabundance is a part.
More grain is being diverted from food into the making of alternative fuels, Waxman said.
Meanwhile, more people in India and China are eating meat, siphoning larger proportions of the world's grain supplies to feed the livestock.
Higher commodities prices are reflected in more expensive milk, eggs, and produce, Waxman said.
In the last year, eggs have gone up as much as 13 percent and milk has increased 11 percent, federal figures show.
On average, middle-class Americans spend 10 percent of their household budgets on food, federal figures show. But the poor can spend as much as 20 percent, said Craig Gundersen, executive director of the National Soybean Research Laboratory at the University of Illinois.
With fewer resources, the poor must spend more of their money on basic needs, said Gundersen, an expert on food stamps and hunger.
Federal safety-net programs can help the poor. But research at Drexel University's School of Public Health shows that even a family receiving the maximum amount of food stamps would still require an additional $2,600 annually just to be able to buy the minimum amount of food it needs to survive, as determined by the USDA.
The maximum monthly food-stamp payout for a family of four in Pennsylvania is $668. But the average family of four receives around $530.
The food struggles that families endure cannot be hidden from children, who are more aware of problems than had been thought, according to Drexel's Mariana Chilton, one of the nation's leading hunger experts.
"In our newest work, we are finding that children as young as 5 and 6 years old are noticing when their moms are not eating, and will beg them to eat, or say they're not hungry so their moms could eat," Chilton said. "It deepens the anguish that parents feel and deepens children's depression."
Nadja Brickle, 22, a West Philadelphia mother of three, concurred.
"You see the expression on their faces in the grocery store when they want food and you have to say no," Brickle said. "When I cook, I often don't eat so my kids can.
"Most people don't know what it feels like to have your stomach completely empty and to make and smell food you won't be eating. And then, they're not satisfied 'cause it's not enough food for them. And you're still hungry."
A recent issue of the Journal of Nutrition studied children 9 through 16 and their awareness of lack of food in their families. It causes worry, sadness, and anger, researchers said.
Sometimes, older children took matters into their own hands, trying to borrow food from others or looking for menial work to buy food for their families.
In one extreme case, children set up dog fights to make money for food, the Journal reported.
With aware children sharing the pain of hunger, Shontaya Moses said, she has little choice but to face her problems and try her best.
"I team up with people in my building to share whatever food we have," Moses said. "The only thing I can say is, we try to hang in there."
Contact staff writer Alfred Lubrano at 215-854-4969 or firstname.lastname@example.org. Read his blog, "The Joint Custodian," at www.philly.com/jointcustodian