I heard from my chemistry teacher that if you drink a Coca Cola you will get quick energy boost but after 40 minutes or so the takein of such a soft drink will actually result in a net loss of energy partly because it is a cold drink and partly because of the drink itself.

Is it true?

If we compare the same amount of carrot juice and Coca Cola or Mountain Dew or Jolt, how big is the difference in energy difference from taking it?

  • Did your teacher perhaps mean the low enery, after the sugar rush? If you eat or drink food with a high glycemic index, your blood sugar will rise fast and as fast decrease most of the times lower than before. This leaves you with an loss of "energy".
    – Julian
    Mar 10, 2017 at 8:27
  • Related: skeptics.stackexchange.com/questions/23289/… Mar 10, 2017 at 13:45

3 Answers 3



The caffeine content in a normal 330ml coke does promote thermogenesis through metabolic stimulation but the amount it does this is so small that it is negligible.

Cold drinks do not cause you to expend significant amounts of energy heating them up either.

If you want to know the amount of energy a drink will provide then just look at the caloric content on the label.


With numbers:

  • It takes 1J to heat a g of water by about 0.24K. Hence, heating 330ml of colored+sugared water from 7°C (fridge) to 37°C (body temperature): 330 * 30 / 0.24 = 41250 J = 9852 cal = 9.8 kcal
  • Energy content from the sugar of your coke: 330ml * (10g/100ml) * 4kcal/g = 132 kcal

So you can heat a lot of water with the energy content of a coke.

Whatever makes you drowsy is certainly a physiological effect as aluded to in the other answers.

If that had been your biology teacher, his statement would have been fine; from a chemistry teacher I would not expect that!


As JJosaur says, calorifically, it's a definite "No".

However, Metabolically, you may well find that you are more tired an hour after drinking a Coke (or any other sugarry drink, or a chocolate bar), due to a "Sugar" or "Glucose" crash.

This is period of low blood-sugar caused by the body over-compensating to the sugar spike (the initial 'high', or 'sugar rush'), and over-producing insulin which then draws that glucose out of the blood stream into the liver for longer-term storage.

The low blood-sugar can be experienced as fatique or loss of energy (amongst other symptoms), which might lead one to believe the original claim.

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