How do you know which fats have more energy?

How do you know which fatty acid chain has more energy? Does it depend on if it has double bonds, the number of carbons or the number of hydrogens?
Does an unsaturated fat contain more energy than a saturated fat?

Unsaturated fats have less energy than saturated fats. This is because the double bonded carbons in the the unsaturated fats cause the hydrogen atoms to be eliminated. Hydrogen-carbon bonds are the source of energy in fats and since there are less of these bonds in unsaturated fats there is less energy.