Vegan fast food is full of salt, high in fat and have none of the nutrients that animal products have to offer. This high salt and nutrient deficient diet can cause brain fog, weight gain and fatigue.Vegan fast food is full of salt, high in fat and have none of the nutrients that animal products have to offer. This high salt and nutrient deficient diet can cause brain fog, weight gain and fatigue.Read MoreHealth News | Mail Online