"Search Type" only appears in the AI menu generator if you have a meal-category group named "Diet." It has two settings:

• OR (default) — every category, including Diet categories, keeps its own numeric quantity box. Each category is filled independently; picking a quantity for a Diet category just pulls that many random meals tagged with it, with no cross-filtering against your other picks.
• AND — Diet categories switch from quantity boxes to checkboxes. Check the diet tags you want, and every meal pulled for every category with a quantity set (not just Diet ones) must also match those diet tags. A second dropdown then appears, defaulting to OR (default), letting you choose whether a meal must match any one of your checked diet tags or all of them — e.g. Vegan and Gluten-Free rather than either one.