Take a high potency multivitamin/mineral that doesn't contain iron...this is always the basis to a good supplemental program. Since you like sports, I would also suggest a good adaptogenic herb like American Ginseng, or Siberian Ginseng or Rhodiola Rosea. Adaptogens are herbs that balance the body. They increase your resistance to physical and mental stress, they calm the mind, energize the body, increase stamina level during exercise and improve your immune system and general health. Concerning your diet, try to eat many fresh fruits and veggies, drink lots of pure water, include beneficial fatty acids like flax seeds and stay away as much as possible from fast food...good luck ;-))