What role do Mental and Physical fitness play in the life of a Jedi? Well, working in unison, they play quite a role. But, as with many aspects of Jedi life, they must both be balanced to be most effective. Especially for younger Jedi who are not yet as strong in the force (And I say younger related to the length of their training, not their physical age) physical training is especially important. You'll notice that in the movie, both young Jedi (Obi-Wan in Phantom Menace, and Luke Skywalker) are both very physically fit. Obi-Wan in particuar is strong in swordplay, as he demonstrated against Darth Maul. The reason that physical fitness is especially important to both of these young Jedi is that neither are yet fully trained in the force, and often must resort to physical prowess to survive. One of the aspects of the force that we Jedi train in is the ability to "foresee" events a split second ahead of time. As you can imagine, this does come in handy...and if you lack that ability, you must make up for it in some way (physical agility and strength). For an older Jedi, physical strength starts to become slightly less important. It is still important to be physically fit, but as you become stronger in the force, you are less likely to even need to use physical force. Mental strength becomes more important as your Jedi training progresses. I loathe to use another movie example, but I will...Yoda is a prime example of this. He had not drawn his lightsaber in many years when he died, because there was no need to do so. As a Jedi Master, his strong connection to the Force was more than enough to protect him...also, it takes such a long time to truly master the force that his body had begun to wear down through time.
As a student or Padawan whose connection to the Force is not yet fully developed, it is important to eat a controlled diet, and exercise regularly. For young students who are not yet into their teens, regular play and healthy meals should be enough. But for older students, whatever your age, physical conditioning is imperative. Also, remember that your diet has a direct effect on the way your mind operates. You will not be able to attain your fullest mental strength, if you live an unhealthy life. My personal regimen consists of such:
5 balanced, smaller meals. These are usually made up primarily of grains, such as bread, noodles, rice, etc. I also eat a sampling of fruits and vegetables, and portions of meat, as the iron they contain is vital. I also drink large amounts of water, especially when working out.
2 hours per day of working out. For most students, this is excessive...start small, work your way up. As an athlete, I have a stronger workout routine than you should begin with. I do about 10 minutes of walking, 30 minutes of jogging, then another 10 minutes of cooldown time, in which I return to a walking pace and eventually stop and stretch. After that, I usually have about an hour's worth of weights and power movement. Balance is key: You don't want a huge upper body, and no leg strength. If anything, having strong legs is even more important, because it gives you a strong foundation to work off of, and gives you agility and movement.
As young students, try to follow a similar balanced diet as I do. Anyone, regardless of age, can eat a healthy diet and benefit from it. Start with something minor...cut out sodas or candy bars from your diet, and work from there. The occassional treat is okay (I'm addicted to Iced Mocha Frappucinos). As far as the workout regimen, try to cut it down quite a bit. Maybe a bit of running...until you've worked up a threat. Older Students can accent their workout with small amounts of weights...don't do too much, you can hurt yourself unless you're under professional supervision.
Follow these steps, and they will go a long way towards enhancing your training. But remember: Balance, Moderation, and Wisdom!
May the force be with you, and may you use it wisely.