...she is a waitress in an Italian restaurant. The folks she works for actually own two restaurants just to achieve and maintain their desired standard of living. The husband runs one and the wife the other. They are there every night and definitely weekends.
This is probably the most important truth you have to come to grips with.
As a programmer, you get paid regularly regardless. You can have days where you are sick, unproductive, cranky or whatever and that check still arrives. The food business is NOT A JOB, it is a LIFESTYLE. You will be married to it. You will spend more time at your restaurant/vending booth then you spend at home. If you take a day off, everything grinds to a halt and you will lose money. (Yes, even if you have employees, unless you can afford to pay somebody the $30K a year it takes to get somebody who cares about your business)
I know what I am talking about - I work as a programmer and am a partner in a BBQ Restaurant. My partner and/or his wife are there six days a week, 52 weeks a year. There is no way I would choose to quit my IT job and work in the food business full time - it requires a tremendous commitment for a marginal return in addition to great financial risk to capitalize a business with the highest probability of failure of any start up.
All that said, go for it if preparing food is such an overwhelming passion that you think about it all the time and you reap great satisfaction from doing the hands on work. However, if you are looking at this move as an easy alternative for providing for your family you would be making a huge mistake; better to figure out how to become more competitive in your field and keep BBQ as a fun hobby.
I'm not trying to discourage you, just to help make you aware of the reality of the biz.
EDIT - Oh and one other thing: If you don't like dealing with the public, don't even think about it! Folks have many choices when they to go out eat, and the one thing a small operator can offer that the franchises can't is personalized service. Your customers will return to dine because of YOU. If schmoozing with customers doesn't sound like something you want to do you're in big trouble before you start. Only you can be the owner - you can't hire a stand-in.