Can a restaurant list food in the WhatsApp catalog without breaking the rules?

Yes, as long as each item has a unique title, at least one image and a country of origin, passes WhatsApp's review, and is not a restricted product such as alcohol or tobacco.

• Each item needs a unique title, at least one image and a country of origin. Price, description and product code are optional.
• Review: items show to customers only after WhatsApp approves them. A rejected item shows a red exclamation icon, and you can request another review.
• Not allowed: alcohol and tobacco, including hookahs, even with a local license. WhatsApp may bar you from some or all of WhatsApp for Business.
• Your duty: catalog items must follow the Meta Commerce Policy, and you are responsible for taxes, sales terms and fulfilling orders.
• Prices: adding prices to a catalog is available only in certain countries.