vs. Carbs    &    Energy Storage

      1 gram of Carbs (glycogen)    =    about 4 Kcal of energy   - a short term rapid energy source
                                                                                                                        (sprint events)

      1 gram of Fats                             =    about 9 kcal of energy   - a long term energy source
                                                                                                                        (endurance events - marathons)

          Average human contains about 0.5 Kg of stored glycogen  =      2,000  Kcal of energy
                                                    and about 16 Kg of body fat                   =  144,000  Kcal
                           to carry the same amount of energy [144,000 Kcal] as carbs
                                we would have to store 36 Kg [79.4 lb] more of glycogen

                           to loose 1 Kg of body fat means you need to burn lots of calories.