More than 60 percent of Gaza residents needed food aid even before the latest Israeli bombing campaign started on October 7 in the wake of deadly Hamas attacks inside Israel.

Gaza, which is 10km (6 miles) wide and 41km (25 miles) long, is home to 2.3 million people who have been under an Israeli land, sea and air blockade since 2007. They have faced five military offensives since Israeli soldiers and settlers withdrew from the enclave in 2005.

The humanitarian situation in Gaza has become “catastrophic”, UN agencies say, because Israel has cut off supplies of food, water, fuel and electricity.

What is the food situation like in Gaza now?

Gaza’s entire population faces food shortages, according to a joint report by the United Nations’ World Food Programme (WFP) and Food and Agriculture Organization (FAO).

“The destruction [by the Israeli strikes] has severely disrupted the food supply chains in Gaza,” it said.

Israel has allowed three convoys of aid trucks to cross from Egypt into Gaza, but up to 100 trucks carrying essential aid are waiting in Egypt for approval to leave.

With several bakeries bombed and others shutting down because there isn’t enough water or power, UN agencies, including the WFP, are able to provide bread for just one meal a day.

Kifah Qudeh is staying at a shelter run by the UN Relief and Works Agency for Palestine Refugees (UNRWA) at the Ahmed Abdelaziz School in Khan Younis in southern Gaza. He told Al Jazeera that every two to three days, he is given three pieces of flat bread and is allowed to fill up four bottles of water to sustain his wife and three children.

“We cut one piece of bread in half, and if we have access to jam or something else, we put that inside and give it to the children. If not, it’s plain bread. It’s not enough to sustain us, but it’s all we have,” he said.

Is food scarcity now worse than before?

The situation is dire with no one aware how much longer their limited food supplies will last. Shops that have so far survived air strikes have empty shelves and no way to restock. Many people left their homes in a rush without money after Israel started air strikes on October 7. Not everyone can afford to buy what little is still available.

Food supplies were already limited under Israel’s 16-year blockade of Gaza although Qudeh says at least he was able to pick up a bag of six or seven fresh flatbreads every day from Gaza’s bakeries. It was enough to feed his family. “We’d eat this with some canned cheese or hummus if we could get it.”

Even before the current war, food entering Gaza was mainly canned goods and processed foods like “tinned cheese, potato chips and instant noodles – ultraprocessed foods that are known to cause health issues”, Iman Farajallah, a Palestinian psychotherapist based in California, told Al Jazeera.

As a result, Gaza residents suffer from malnourishment, said Yusra Eshaq, a nutritionist based in the United Kingdom.

“Palestinians in Gaza have already been malnourished for years, and for their bodies to now further endure food rationing, it will take a real toll,” she said.

With a dramatic drop in calories, the body will start to break down fat and then later muscle mass. This is the danger zone when organs can start to fail, Eshaq explained.

How has 16 years of the Israeli blockade impacted Gaza?

Farajallah, who grew up in Gaza in the 1990s, said: “We’d eat a breakfast of locally grown tomatoes and cucumbers, homemade cheese that my mother would make from fresh milk and eggs from the chickens that many homes once kept. It honestly feels like another lifetime.”

She left Gaza for California about 20 years ago to continue her studies and become a psychotherapist, but she knows all too well the realities on the ground from her trips back to visit family and from the regular calls in between.

“Palestinians like to eat together as a family and not just dinner but three times a day. We’d have dishes of maqlouba [a layered dish of meat, vegetables and rice] and mansaf [lamb cooked in fermented yogurt] and warak anab [stuffed grape leaves], but later under the Israeli blockade, meat became a rarity only to be consumed on Eid al-Adha, and that was if there was a way for the livestock to enter Gaza,” she said by phone.

Her family who remained in Gaza started to eat less because the processed foods came at a price and the Gaza economy had begun to suffer from limited trade and travel.

“My sister in Gaza started to change her dishes because of a lack of food. Whereas she may have roasted stuffed chicken with nuts and raisins, under the blockade if she was able to get chicken, she’d boil it to make a simple soup for her kids, a treat for her family, and they’d eat this with bread,” Farajallah said.

Does Gaza still have water?

Gaza has water for now, but it’s limited and often contaminated and tastes salty.

Gaza’s only subterranean aquifer is exhausted, meaning water is unsanitary to drink and can’t be used to water plants.

The UN says 97 percent of Gaza’s water does not meet World Health Organization (WHO) standards.

Palestinians living in the enclave have became reliant on private water tanks and small desalination plants for their drinking water.

The last desalination station stopped working on Tuesday when its fuel ran out. Israel said it has renewed its water supplies to southern Gaza, but Palestinians said many water pipes have been damaged in the recent Israeli shelling. And without electricity, water pumps to fill the tanks are not working.

Qudeh said: “We are among the lucky ones. … We have some water.” Every two days he is able to fill four plastic bottles of water from UNRWA supplies.

But he’s careful to ration for himself and his family.

“We try to stick to a glassful a day. It’s difficult not to gulp it down, but we are aware of the situation and have to be careful with what we have to make it last,” he said.

Other Palestinians have described on social media how they are rationing food and making sure children eat and drink first.

If water runs out, how long can one survive?

A WFP nutrition specialist based in Jerusalem told Al Jazeera a healthy adult can live up to 10 days without water and a child up to five days.

Our bodies are made up of 75 percent water, and adults should drink about 2.5 to 3 litres of water a day for their bodies to function at optimum health. But shortages mean people are drinking less water.

“Yes, we need water for our body to work, from our brains to our kidneys to our hearts. It runs through our blood, our digestive juices, our sweat. And if we don’t have it, we die,” Eshaq said.

The first effects of dehydration can start on the first day with too little water. “So someone may feel dizzy and light-headed and will have a dry mouth,” she said, adding that such a condition can quickly cause reduced cognitive functions.