I’m an educator and the only thing that significantly impacts IQ is traumatic brain injury or starvation. Starvation can result in about a 15 point drop (one standard deviation), and that can be changed back by nourishing the person. There is a lot of misinformation out there about how food affects the brain. Typically the only thing that affects it is lack of food or if you have some type of allergy to a specific food.
