How much more energy can fat store compared to glycogen in a given unit of storage mass?

Fat is a highly energy-dense nutrient, providing about 9 calories per gram, whereas glycogen, the storage form of carbohydrates in the body, provides about 4 calories per gram. This significant difference in caloric content makes fat a much more efficient form of energy storage.

To determine how much more energy fat can store compared to glycogen, you can calculate using the respective energy values. Since fat provides nearly double the energy per gram compared to glycogen, the calculation shows that fat can store approximately 2.25 times more energy than glycogen when looking at a mass-based comparison.

However, this figure doesn’t take into account the fact that glycogen holds water (approximately 3-4 grams of water for each gram of glycogen stored). If you consider the weight of glycogen due to the water it retains, the effective energy storage capability of fat increases. When factoring in the water, fat can provide even more than the simple 2.25 ratio because glycogen's storage weight increases substantially due to the water it binds.

In practical terms, when all calculations and factors are considered, fat can store approximately 6 times more energy than glycogen on a weight-adjusted basis, which aligns perfectly with the correct answer.