Higher-lactose dairy foods to avoid on a low-lactose diet include mammal milks, yogurt, soft cheeses, cream, and foods prepared with any of the above (such as milk pudding, barfi, ice cream, gulab jamun, milk bread, scalloped potatoes, cream sauces and soups, etc.).
Lower-lactose dairy foods, which may be tolerable without symptoms, include lactose-free milks and creams (mammalian milk/cream which has been pretreated with lactase enzyme), hard cheeses (parmesan, swiss, cheddar, etc.), and all plant-based milks and cheeses, which are naturally lactose-free.[1]
A special note on whey protein: Whey, a byproduct of cheesemaking, contains plenty of lactose. Whey protein concentrate (WPC) contains varying amounts of lactose, depending on how it’s processed.[2] Fortunately, whey protein isolate is low-lactose, although not completely lactose-free.[3] Some brands of whey protein concentrate and isolate list lactose content on the label.