First of all, congratulations on your success. I know it can feel so stressful and scary at times so I am glad you have found a place to come for peace of mind.
Second, what a great question. The truth is you are not required by law to provide a lunch break (I know many people think you are, but federal law does not mandate it) HOWEVER consider not only what is best for profits but what is best for employee moral.
I will say that I agree with the previous posters who suggested speak with the employees about it. At the end of the day you want to find a win win situation and you really need to hear what they would consider a win to accomplish that.
I will offer that in my window cleaning business, the guys eat 90% of their meals in the truck. They can stop and get food anywhere they feel like but the customers are expecting them at their residence or business at a specific time and that really does need to be met so it is up to them how they get that done. Now we also allow for time to eat when we are scheduling the jobs which is important to consider as well.
I hope this helps
Best of luck,