This topic looks a lot like the one you started 14 months ago.
Health of chess players

That's why chess can't be considerd a sport. Most chess players look unfit. When playing online chess (turn based), I do stretching exercises. Sitting long hours is unhealthy. http://www.medicalnewstoday.com/articles/256663.php

I would say that being physically fit allows you to sit for longer at the board without feeling fatigued, thus giving greater concentration. I used to enjoy a pint of beer with my game but now tend to favour a soft drink and maybe grab a beer after the game or at a point when the position is winning easily in my favour.

reddersn - Former world champ Anand worked out and lost a significant amount of weight before his match with Carlsen. I guess that he would agree with you about the importance of being physically fit!

If you look at the 10 best players according to the World Rankings, they look pretty fit to me. It goes without saying that you need to be healthy if you want to play at this level.
And Carlsen pratically lift every weeek.

Kidding aside, I think a good health is always a benefit to your mental state and your performance in just about everything.

Kasparov, considered best all time, is probably the fittest world champion. I've read articles he swims long distance in the open sea. And his energetic plays on the chess board shows it.

Aerobic exercise is important for your heart, as you can be under a lot of stress during a tournament, you need your heart to be strong.
Anaerobic exercise also makes your heart stronger and also helps with the stress.
Both types are good to get rid of the extra energy we build up from being seated for long hours.
It is also proven that more blood flows through your brain, which means more nutrients and more oxygen = Better performance.
Exercise also increases oxygen flow to the brain thus increasing brain activity, I found this out last year when I was doing weights. I stopped in June due to a pulled ligament and only started again 2 weeks ago. My chess has improved after dropping when I stopped

My own grade and playing performances have improved this year due to regular exercise and no more increase in chess study. I also stay away from certain foods such as pies and pastries and sugary drinks and match days. Otherwise I tend to feel sleeoy and tired.
I have noticed that a large amount of weekend chess congress warriors are suffering from both poor physical health (obesity) and mental issues (plastic bag shufflers). As a regular exerciser, I see the benefits of improved performences over the board. I welcome a discussion on this topic (chess playing triathlete)