Labels are required on packaged food. A lot of what you'll eat isn't packaged. Restaurants and cafés don't have to list ingredients, and menus rarely do. Bakeries, deli counters, department store food halls and markets often sell food unwrapped, with just a name. Konbini and supermarket packs are the easy case: the label is on the back. If nobody can tell you, it's fine to walk away. There's always a konbini nearby.