There are some people at work (they know who they are) who love scheduling meetings during lunch. Those people are assholes, and now it's a proven fact.
Michael Rosbash, together with Jeffrey Hall and Michael Young, won this year's Nobel in Medicine by proving that a person's happiness is affected by a "temporary mismatch between our external environment and [the] internal biological clock". Basically, if someone (like a very annoying co-worker) delays your lunch time, it causes you to be unhappy. Duh! Now proven by Nobel laureates.
It goes beyond lunch, of course. Sleep patterns clearly have a large effect, so it's very important to go to bed at the same time every night. (You were right, mom!)
It's worse than just unhappiness. That mismatch can increase the risk of diabetes, Alzheimer's, and cancer.
Lunch meetings cause cancer! You know who you are, people at work!