The warning came from Wong Wing-hang who specializes in gastroenterology and hepatology.

The doctor is alarmed by the poor eating habits of city dwellers after dealing with cancer patients who are in their 20s and 30s.

Esophageal cancer is linked to a gastric disorder, medically called gastroesophageal reflux disease when stomach acids go back up into the esophagus.

The acid reflux causes pain, which is often called heartburn and can disrupt sleep and make eating difficult.

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Wong explained more gastric acid would be secreted to digest the late suppers and food hastily gulped down.

They will become vulnerable to gastroesophageal reflux disease or acid reflux when the lower esophageal sphincter does not close properly and the stomach contents leaks back into the esophagus.

"It easily happens when people have late meals and sleep immediately after their stomach is full."

He warned that chronic reflux of acid would inflame the esophagus lining which can lead to cancer in the most severe cases.

Findings show 1 percent of patients with gastroesophageal reflux disease would develop a more severe condition known as Barrett's esophagus.

People with this condition have 30 times higher risk of developing esophageal cancer. Hong Kong has 4,000 new cases of gastroesophageal reflux disease a year, three times higher than a decade ago.