My wife regularly has a runny nose when she starts eating. She does not have a runny nose otherwise. She wants to know if this is normal?

Gustatory rhinitis. This is called gustatory rhinitis. It is not as common as allergic rhinitis, but many people do suffer from it. The most effective treatment appears to be topical Atropine before eating.
Very normal. Most people's nose run more when they eat. Some run dramatically. There is a prescription spray called atrovent (ipratropium) which can be very helpful. My family friends and staff all know when I am done eating because i always have to blow my nose!