Why is the status of a whole food one value, and an extract or preparation of the food rated the opposite?

The lectin content or antigenic propensity (allergy potential) of certain foods is modified by processing. In some cases the unhealthier form (i.e processed bread) may be acceptable if heat or milling has removed the lectin from the food. Other times processing enhances the effect of a lectin, so the native form is acceptable, but the processed form is not.