A Syrian soldier walks past destroyed buildings in eastern Aleppo’s Baadeen district Monday, a day after government forces took control of the area from rebels. Residents who remain in the still-blockaded parts of the city’s east face starvation. (George Ourfalian/AFP/Getty Images)

With its stockpile of food dwindling rapidly and government forces tightening their stranglehold on rebel-held eastern Aleppo, the Khattab family dreads what could come next. The brutal blockade has brought the family’s side of the city close to starvation, while punishing airstrikes have turned trips to local markets into life-or-death excursions.

Over the weekend, Syrian President Bashar al-Assad’s forces made major advances against the remaining rebel enclaves, but even as thousands of residents flee, many others are refusing to leave, fearing capture.

Those who are staying have very little left after years of war and months of a near-total blockade.

“We’re only eating two small meals a day now, and it’s just rice and cracked wheat,” said Moataz Khattab, 26, who lives with nine family members. “We eat together, what we can, but we are losing so much weight. We’re running out of supplies, and now we talk about starving to death.”

Last week, Jan Egeland, a senior U.N. humanitarian adviser, warned of impending starvation if efforts to bring in aid continue to falter.

Syrian soldiers inspect damage in a street in eastern Aleppo's Bustan al-Basha neighborhood Monday. Government forces captured six rebel-held districts in the city’s east over the weekend, forcing thousands of residents to flee. (George Ourfalian/AFP/Getty Images)

Since Sunday, rebel defenses in Aleppo — divided since 2012 between rebels in the east and government-held districts in the west — have started unraveling. Government forces have seized more than a third of the east, prompting more than 16,000 people to leave the area, according to Stephen O’Brien, the U.N. humanitarian chief.

What comes next could be a final deadly assault or an even tighter siege to starve the remaining rebels into submission. For the past four months, Assad’s forces have blockaded more than 200,000 people in the east, nearly half of them children, according to U.N. officials.

Those who remain trapped there must contend with frigid winter temperatures and lack of access to fresh supplies of food and other essentials, such as drinking water, fuel and medicine.

“Every day, my children ask me for food that is not available. They want fruit. They want chicken. They’re hungry,” said Ali al-Halabi, a 36-year-old father of three who lives in the area.

He has also reduced his family’s meals from three per day to two, and he’s begun contemplating eating just once daily himself. The family’s food stockpile is almost exhausted, he said.

Aleppo, the nation’s commercial hub and its largest city, was once a symbol of the rebellion against Assad. Half of its districts fell quickly to the rebels in 2012, and it was expected to become the staging ground for the Syrian leader’s eventual overthrow.

That overthrow never came, however, and nearly 400,000 people were killed in the civil war that saw Russia, Iran and other Syrian allies step in to support the government and turn the tide of the war.

Now eastern Aleppo is a symbol of desperation. Airstrikes have leveled hospitals, homes and much of the infrastructure, with people surviving on vegetables grown in backyard plots.

Its residents know what horrors still await them, having watched rebel-controlled towns and neighborhoods across the country succumb to the government’s harshly efficient starvation sieges.

U.N. officials and aid workers say scores of Syrians have died under these blockades from the effects of malnutrition.

Dozens just in the town of Madaya, west of Damascus, died when the food ran out. The world was shocked earlier this year by a flurry of images from Madaya that showed residents looking deathly ill, some so thin they resembled walking skeletons.

Khattab, who said he has lost 15 pounds just in the past few weeks, actually thinks he and his family members are fairly lucky, considering the situation. They stockpiled a relatively large amount of food, although they have now whittled down their supplies to alarmingly low levels.

The family’s less fortunate neighbors have run out of food, and one boy in Khattab’s district is close to death, he said. “He has become a skeleton,” Khattab said. “Neighbors donated food to him, but it won’t last long.”

Khattab’s mother, 52-year-old Hend, tries to come up with creative ways of cooking the family’s remaining supplies of cracked wheat and rice. But the declining portion sizes — and lack of nutrients — are taking a toll, especially on younger family members.

Khattab is particularly concerned for his 10-year-old brother, Mohammed. “He’s so young, and he’s not getting the foods he needs to be healthy,” he said. “It’s dangerous for him.”

For Khattab, it is becoming hard just to make it out the door each day to pursue his work as a freelance photographer chronicling the devastating aftermaths of countless airstrikes.

“You just stay at home, rest, and that’s it,” he said. “You don’t have energy.”

It is a condition afflicting many of the young men who keep eastern Aleppo running. Raed al-Saleh, the head of the Syria Civil Defense Force or “White Helmets,” said his team of volunteers, who play a vital role in retrieving people from the wreckage of buildings bombed by government forces, show signs of worsening fatigue from the lack of food.

The lack of energy makes their lifesaving work much harder, said Abu Laith, 26, a White Helmet rescuer who said he is subsisting on rice.

“These are the worst days of the war,” he said. “We’re exhausted. We’re so exhausted.”

Louisa Loveluck in Beirut and Heba Habib in Stockholm contributed to this report.