Do you think which is better to have lunch on desk or away from desk and why ?

Away from desk. 

You can socialize, have fun, learn someting new and more importantly get refreshed before you get back to business

It's always better to have lunch in the designated areas to maintain the decoram of the office and most importantly the fragrance of ur food may distract others, working on something serious or urgent task. Moreover lunch time is the time to relax and to release the stress and hang out with colleagues. So we should enjoy the time by going out instead sitting on ur desk...

It is better to have lunch away from desk.

It is experienced and observed that many office based jobs where workers used to do routine tasks on a specific work area / station. Physically and mentally this is necessity for everyone to change the environment for some time. It will also improve the creative abilities of the workers if they relocate themselves and spend at least few minutes in a changed surroundings..

Lunch should be away from disk to recharge positive energy

away from your desk to take a break from the computer screen.

Lunch should be away from desk for reasons being that you need to know there is a moment for everything and a place for each activity and focus and concentration should be given at any point of activity. To add lunch is also a moment of strech and relaxation which should be out of desk

Lunch  is a break away from the desk is preferred for mind refreshments.