I have 4 of them

My 11 year old was like that and really chunked up for awhile. I was so worried. Puberty is hitting now and she is getting taller. She is also not eating the same things since I no longer have them available to her.
My 3 and 4 year old do this now. I noticed that boredom eating turned into a habit. I started serving a meal and then planning an activity right after. I would tell them that they needed to eat so we could play Memory or Hungry Hungry Hippo. Once I got their minds off of it, they slowed down and didnt focus on the meal.
They really do this when I dont have organized meals. I graze throughout the day if I am not careful so they are just following my example. I have really been trying to have meals at a certain time and be consistent. They snack on graham crackers and apples for the most part. I make them drink one glass of water for one glass of anything else. It really is working for us.
I wish you the best and hope you find a solution that works for your family