Question

What are TWO reasons that fats are generally more energy-dense than carbohydrates?

Fats are less hydrated than carbohydrates.

Fats are more hydrated than carbohydrates.

Carbon in fats is generally more reduced than carbon in carbohydrates.

Carbon in fats is generally more oxidized than carbon in carbohydrates.

Carbohydrates are stored in special membrane-bound compartments that take up more space.

Answer 1

Literature and experiments explain why fats give more energy (more energy dense) per unit mass than the carbohydrates. There are several explanations, however, I find it simple and easy. Fats have more reduced form of carbon than carbohydrates which enable more energy release when oxidized to CO_2. It is seen that fats provide almost 9kcal of energy per gram whereas carbohydrates give 4kcal/gram. Another reason I find is that the fats are generally non-polar and hence are anhydrous. Carbohydrates and proteins are more polar than fats and hence are hydrated which results in low energy yield. Consequently, fats provide almost six times more energy than carbohydrates. So only body stores energy as fats.

So Answer here will be,

Fats are less hydrated than carbohydrates.

and Carbon in fats is generally more reduced than carbon in carbohydrates.