This is just down to nothing more then poor discipline and lazily wanting an office to fill the gap for you. I have been working from home for 9 years now, 5 days a week. You know how I solve the issue, I go outside. I go and run. I take my dogs out for a walk. I also meet with friends to eat / drink coffee. I look after myself. The time I save commuting means I can do things like cook myself a proper lunch, go and have a nap if I did not sleep great the night before. I have much more freedom to balance my life. I agree though, if I sit at my desk all day inside and then stop work to go and sit on the couch and watch Netflix, sure it's going to be detrimental to my mental health.