The government has bombed at least 25 hospitals and clinics, and has killed or arrested dozens of doctors.
Medicines are in short supply, with field hospitals in many areas critically lacking staff, basic drugs, bandages and equipment
There are mass graves in at least eight locations, and suspicions of others that cant be checked out.
But the food shortage was the biggest concern of the 30 respondents who took part in the survey.
The Sahel al Ghab plain, in Hama province, used to be one of Syrias richest agricultural regions, producing grain, olives, rice, cotton and sugar. But this year has been disastrous because of the war. Several people from the area said their land wasnt being farmed because of shellfire from regime-loyal villages.
Sahel al Ghab has a mix of Alawite villages, which are mostly loyal to Assad, and Sunni villages that were among the first to rise up against him. Tamam Salloum, from the Sunni village of al Huwaiz, said farmers were prime targets for regime-loyal shabiha militia.
We have found bodies in the river Orontes, in plastic sacks, he told McClatchy. The regime arrested farmers, tortured them, tied them with rope, cut them with machetes, shot them mostly in the head or the chest then put them in sacks and dumped them in the river. We took them out and buried them.
Mohammad al Turki, a fighter with the Tahrir Brigade in Hama, said a severe shortage of diesel fuel was another reason for the collapse in agriculture.
Also there is a lack of fertilizer, he said. Regime tanks have destroyed irrigation canals. Army units are present in agricultural areas, and the army is stopping workers from getting to the land.
Deir el Zour, in the east of the country near the Iraqi border, has lost most of its population of 280,000, with many residents moving north to the provinces of Hasaka and Raqqa. Those who remain rely on a trickle of bread brought in from Hasaka, 170 miles away.
Some cars carrying just bread have been shelled, said Adday, the businessman whos living in Saudi Arabia. There are some organizations bringing food to Deir el Zour from other cities, but the people delivering it have been killed by snipers at the same numbers as people who are actually fighting.
He said one elderly man had died of hunger because he was trapped in an area that was under bombardment and nobody could reach him.
In Latakia, on Syrias Mediterranean coast, crucial supplies of grain from other provinces have slowed to a trickle, according to Abu Hadi, the Jablah activist, who now organizes aid deliveries from across the Turkish border. He accused the regime of systematically cutting off food even to its own supporters, then blaming the rebels for the shortages.
Abbas Muhabiddin, a businessman from the besieged town of Qusayr in Homs province, arrived in Ankara after a perilous four-day journey, zigzagging across Syria to avoid regime checkpoints. He said the biggest need in his town was bread.
To make bread we need an oven, we need flour and we need fuel, he said. Seventy percent of our need (for bread) is not being met.
Flour and fuel once were supported by heavy government subsidies, but these have stopped. The price bakeries pay for a quart of diesel fuel has shot up to more than a dollar from just under 10 cents. The town has been under heavy bombardment for weeks, and its economy is at a standstill.
Muhabiddin said some people had been going to other areas to buy bread, such as the city of Homs, but that three had been killed. With the rapid devaluation of the Syrian pound and a surge in fuel prices, the price of the journey has shot to 1,000 pounds $14 from 7 pounds about 10 cents.
Right now, it is about food and diesel fuel, said Omar Shawaf, an expatriate Syrian engineer who helped organize the conference.
We are at the very abyss now regarding a very severe shortage of food. We dont have enough money to deliver flour, and if we do, we dont have the fuel to operate the bakeries. Most of what we know is the tip of the iceberg, but its becoming clearer that this is a catastrophe.