Food intolerance refers mostly to the inability to process or digest certain foods. A
more severe problem happens when someone develops a true allergic reaction, an
overblown response by the body’s immune system against a seemingly harmless
substance- in this case, a food. After eating certain foods, a large part of the
population experiences symptoms that are not related to food intolerances, food
allergies, or celiac disease. These are referred to as food sensitivities. Though there is
controversy around what exactly happens in the body of someone with a food
sensitivity, it appears that exposure to specific foods may create an immune reaction
that generates a multitude of symptoms. The symptoms are not life threatening, but
they can be quite disruptive and include joint pain, stomach pain, fatigue, rashes, and
brain fog. Gluten is probably one of the best-known trigger of food sensitivities.
The best tool we have to identify food sensitivities is a process of careful observation
and experimentation. Removing certain foods believed to cause reactions from the diet
for two to four weeks, reintroducing them one by one, and watching for symptoms is
the current gold standard to pin down what may be causing symptoms.
(https://www.health.harvard.edu/blog/food-allergy-intolerance-or-sensitivity-whats-the-
difference-and-why-does-it-matter-2020013018736)