The Search Type dropdown appears only if you have a category group named Diet. It changes how diet categories are used:

• Show meals that match any one of the options selected -- OR (default): every category, including diet categories, has its own quantity stepper and is picked independently.
• Show meals that match every option selected -- AND: the diet categories become toggles instead of counters. You set quantities on the other groups (for example 5 Chicken, 3 Beef) and tick diet categories as filters; a second selector, OR (default) / AND, decides whether a picked meal must be in any ticked diet (OR) or in all ticked diets (AND).

With the AND search type and no matching meals, Sprwt returns "There are no meals with those combination requirements." and nothing is added.