What is the reason for the constant desire to chew food, eat during work, even if you ate a heavy meal?

There can be many reasons, a psychologist dealing with eating disorders will tell the true one. Stress, habit, the post-Soviet custom of the grandparents who raised you, to eat up every last crumb, and then suddenly there is war and hunger, "it is customary in the family", boredom. First you need to stop making a cult out of food (suddenly), find an activity that will be interesting to you, you will instantly forget about it. Focus on your work or talk to coworkers, drink tea, or chew gum if you hate it. A person does not live to eat, but eats to live :)

Food is soothing. Sweets also give positive emotions.

When you chew, you feel calmer. And ... safe, or something. After all, when we feel danger, we have no time for food. So I want to create such an illusion of security.

Or just a habit. Since childhood, I used to constantly eat, eat sweets after the main course, etc.

To unlearn - you need to be distracted by something and get emotions from something other than food.

Of course, there is nothing wrong with eating a piece of candy or two once a day, but when the process of eating food becomes permanent and your mouth is clogged with something 24/7, only self-control will help.