This will result in your body attempting to fight the infection, causing plenty of symptoms. Generally you will begin to experience these symptoms around four hours after you have eaten the food, and there will be many of them. Take a look at these 10 symptoms of food poisoning and see if you have been affected by the unpleasant problem. 1. Nausea. The first and most telling sign of food poisoning is nausea. The is the most common symptom and it will be the most significant, causing you to feel sick constantly, and resulting in vomiting that can last for quite some time. At first, you may feel as if you are going to vomit, but you won’t actually vomit.