Answer
Fats are better energy stores than carbohydrates for the following reasons:
1. Carbohydrates are hydrophilic, therefore, they absorb water readily and expand as a result. One consequence of this expansion is that they occupy more space-- mass for mass --than the more compact lipids. Lipids are hydrophobic, they absorb little or no water, and occupy less space in tissues.
2. Fats are less oxidized than carbohydrates and contain about twice the amount of energy as equivalent masses of carbohydrates.
Caloric yield of carbohydrates and fats:
Carbohydrates (and proteins) 4 kcal/gram
Fats 9 kcal/gm
Work Step by Step
A man's fat storage contains 119 hours of running energy, but his carbohydrate energy store can supply only 1.6 hours of running energy .
