I thought this was very interesting though not 100% sure whether to put it in the training or nutrition forum. Also maybe you can let your kids play video games as long as they are standing up?
"There seem to be negative health effects from even short periods â?? a few hours â?? of inactivity: sitting or lying down.
A recent systematic review, first-authored by TJ Saunders of Obesity Panacea, found that a single day of bed rest is sufficient to raise triglycerides, and that 2 hours of sitting increases insulin resistance and impairs glucose tolerance â?? moving the body closer to a diabetic phenotype. 
Research by Marc Hamilton found that sitting shuts down expression of lipoprotein lipase (LPL) in skeletal muscle, preventing muscle cells from importing fat.  A Science Daily article shows an interesting video based on this research. Here are blood samples after consumption of an identical meal eaten the same person; the left sample was taken after a meal eaten sitting down, the right sample after a meal eaten standing:"
"When sitting, dietary fats are taken up only by adipose tissue. When standing, they are taken up by muscle and adipose tissue both.
Time spent standing did more to push fat into muscle cells than vigorous daily exercise. This is significant because pushing nutrients into muscle cells promotes muscle growth. If you have trouble gaining muscle, maybe the problem is too much sitting, and what you need is not more intense workouts, but more frequent standing!"