It is hard to describe what it means for someone to be “severely wasted,” but when you hold a child who is suffering from this most lethal form of acute malnutrition you understand, and you never forget. In Afghanistan last year, I met a 3-month-old girl named Wahida who was so malnourished I could barely feel the weight of her in my arms. Her suffering has left an indelible mark on my heart.

Now the suffering in Gaza is leaving a similar mark on me. Last week, I visited the al-Nasser Hospital in Khan Younis in southern Gaza. Inside, I was met with a sea of patients, health care workers and the displaced. And there were children everywhere: girls and boys running through the corridors, resting on mattresses with their families and recovering in hospital beds. I met a 16-year-old being treated for injuries sustained when her neighborhood was bombed. Though she survived, the doctors say she will never be able to walk again.

The medical staffers were mounting truly heroic efforts to provide lifesaving care to their patients, including dozens of children. But with their supplies of fuel, medicines and water nearly depleted, it is unclear how long they can continue to provide even the most basic of interventions. In the hospital’s neonatal ward, for example, tiny babies were clinging to life in incubators, as doctors worried about how they could keep the machines running without fuel.

These children, Gaza’s youngest — as well as those in utero — are especially vulnerable to the burgeoning crisis of malnutrition and the prospect of starvation. After more than six weeks of war amid bombs and gunfire, a lack of electricity and the near-total closure of all border crossings, Gaza’s one million children are now food insecure, facing what could soon become a public health catastrophe.

Supplies of nutritious food have virtually run out. Shops are closed, and in the streets of Khan Younis I saw piles of garbage where there once were food stands. Last week, the al-Salam Mill in Deir al-Balah was reportedly hit in an attack and forced to shut down. This was Gaza’s last functional flour mill. All local flour production is now effectively halted.

The hostage release deal outlined on Tuesday would include a cease-fire of at least four days and would reportedly allow for some new shipments of basic humanitarian aid to go to the people of Gaza who desperately need it. But to save lives and ensure that Gaza’s population, especially its children, remain healthy and stave off looming health issues, we as humanitarian partners must be permitted to bring quality food, essential nutrition supplies, water and fuel into Gaza, at levels that are sufficient to meet the surging needs. And we must be permitted to continue safely delivering these resources after hostilities resume.

Without sufficient quantities of nutritious food, people will quickly become malnourished and could eventually starve. The risks associated with food insecurity are compounded by the extreme scarcity of safe drinking water. According to international humanitarian standards, one person needs a minimum of almost four gallons of clean water per day for drinking and to meet basic personal needs.

In Gaza, this standard is far from being met: About 96 percent of the water supply is considered unfit for human consumption. Water pumping and wastewater treatment have all ceased to function because of the lack of fuel. People have resorted to accessing water from unsafe sources that are salty or polluted.

These conditions, when combined with displacement and overcrowding in shelters, can quickly lead to disease outbreaks that threaten everyone, especially malnourished children. Since mid-October, more than 71,000 total cases of acute respiratory infections have been reported, while over 22,000 cases of diarrheal infections have been reported in children under the age of 5. And without clean water, health care facilities cannot provide effective treatment to those in need, nor can they maintain basic infection prevention and control measures.

The consequences of this crisis extend not just to survivors of the war but also to those who will be born in its aftermath. The United Nations estimates that 50,000 pregnant women in Gaza — 5,500 of whom are expected to deliver in the next month — can no longer obtain basic antenatal health and nutrition services. Malnourished women are more likely to die and face complications during pregnancy and childbirth. They are more likely to have children born too small, too thin and vulnerable to undernutrition, illness and death. More than 105,000 breastfeeding mothers in Gaza are now struggling to feed themselves and breastfeed their babies. Our analyses show that about half of all stunting in early childhood originates during pregnancy or in the first six months of life — a time when (in the absence of baby formula, which is in extremely short supply in Gaza right now) children are entirely dependent on their mothers for nutrition.

We project that over the next few months, child wasting, the most life-threatening form of malnutrition in children, could increase by nearly 30 percent in Gaza. Up to 5,000 of these children could experience severe wasting, in which dangerous weight loss and acutely weakened immune systems put them at imminent risk of death — even from illnesses like the common cold, other respiratory infections and diarrhea. These are conservative projections; the longer the conflict and siege continue, the higher these figures will rise.

Without urgent therapeutic feeding and care, severely malnourished children may not survive. Even if they do survive, their condition may disrupt their physical growth and cognitive development, with irreversible long-term effects for the vast majority of them. Undernourished and stunted children are more likely to develop chronic health problems as adults, and more likely to have lower educational achievement and economic security.

Even before the current crisis, approximately 30,000 children under the age of 5 in Gaza were experiencing stunted growth, while more than 7,600 suffered from wasting. Now the violence has shut down lifesaving prevention, screening and treatment services for malnutrition that were previously reaching the 340,000 children under 5 years of age in Gaza. With hospitals and health centers ceasing to function and nutrition programs nonoperational, we cannot get malnourished children the critical prevention and treatment services they urgently need.

In the humanitarian community, we use the phrase “time is of the essence” a lot, perhaps to the point where it has lost its ability to convey urgency. But that is exactly the situation we are in right now in Gaza. If we cannot get proper nutrition and care services, safe water and sanitation to children and women now, they will die.

Gaza’s children have endured far too much death and suffering already. In just the last seven weeks, according to Gaza’s Hamas-run health ministry, at least 5,600 children have been killed and nearly 9,000 injured because of the ongoing conflict. We must not let this grim tally rise, especially when the solutions are so evident: sustained, safe and unimpeded humanitarian access to civilians wherever they are, to bring essential food nutrition supplements, fuel and other humanitarian supplies into Gaza. Delays will cost lives.

The parties to this conflict have the power to stop this nutrition crisis from turning into a catastrophe for Gaza’s one million children. I urge them to give us the space to do our jobs so that we can get these kids the support they need and deserve.