Each of these three categories are important for balanced nutrition and good health. Over the years I have kept track of the percentages of macronutrients recommended by various health organizations. Listed below are their recommendations for the percentages of Carbohydrates/Protein/and Fat in your diet.
International Sports & Sciences Association 50-80/ 30 /15
National Academy of Sports Medicine 55-75 / 10-25 / 10-30
American College of Sports Medicine 55-58 / 12-15 /25-30
American Council on Exercise 55-65 /15-20 / 20-30
BYU-Y Be Fit Program 65 /15 / 20
Weight Watchers 45-65 /10-35 /20-35
As you can see, there is still quite a range and some discrepancies even among the experts. My personal opinion for a good balance is 50-60% carbs, 15-20% protein, and 20-25% fat. These are guidelines for the general population. If you have special needs it is always best to consult a nutritionist. It is also important to remember that there are good and bad foods in each of these categories. Not all carbs or fats are created equal. You will most likely eat appropriate ratios of these macronutrients and make healthier food choices if you follow the new USDA food pyramid.