Your question is an excellent one. I've found that many restaurateurs don't immediately see the relationship between F&B and tourism. Let me shed some light:
1. Nearly 100% of tourists dine out when traveling.
2. Dining is consistently one of the top 3 favorite tourist activities.
3. The higher the total dinner bill, the more likely the patrons are tourists.
4. There is a high correlation between tourists who are interested in wine/cuisine and museums, shows, shopping, music and film festivals (which means propensity to stay longer and spend more, perhaps in your restaurant again if they like it).
5. Culinary tourists are highly likely to participate in outdoor recreation. (ditto about staying longer/spending more)
Sources: National Restaurant Assn (U.S.), Travel Industry Assn of America, Canadian Tourism Commission
I'm writing a white paper on the subject that goes into a lot more detail. Let me know if you'd like a copy. It should be done in about a month.