The unit used to measure energy is Joules (J)
Just like we use metres to measure distances, we use Joules to measure a quantify of energy. Note there are 1000J (Joules) in 1 kJ (kilojoule). Another unit that is also commonly used to measure the energy content in food is the calorie (cal) and kilocalorie (Cal).
There is roughly 180kJ (=180,000J) in 100ml of coke. This means an average can contains about 640 KJ. You'd need to run for about 3km to use this amount energy up.