Food intolerance is a digestive-system difficulty processing a particular food component, not an immune reaction, which is what separates it from a true allergy.
Lactose intolerance happens when the body lacks enough of the enzyme lactase to break down the milk sugar lactose, so dairy foods trigger bloating, cramps or nausea.
Fructose intolerance happens when the gut struggles to absorb fructose, the natural sugar in many fruits and honey, leading to similar bloating and stomach upset after eating them.
Gluten intolerance, non-coeliac, is a sensitivity to the gluten protein found in wheat, barley and rye, causing digestive discomfort without the autoimmune damage seen in coeliac disease.
Any one of these three could plausibly explain a reaction like Prashant's sudden vomiting after a meal, since all three involve the digestive system failing to properly handle one specific dietary component.