Yes, hunger can cause vomiting. It can be caused by the acid in your empty stomach. The longer it's been since you ate the worse it can be. Trritation is casued in your stomach and lower esophagus snce the acid doesn't have food to digest, which then gives you the sensation of nausea. This sensation tends to be worse in people with a predisposition to having acid reflux.
In addition if the nausea is extremely transient, such as a sensation going back and forth between extremely hungry and nauseous quickly, it's likely a caused by a strong signal in the gastric nerves and the limited ability of our brains too correctly interpret this signal. So it is likely trying to interpret the extreme range of human gastric sensation and gets the two confused, i.e. hunger or nausea.
