not agreeing with you completly. they have to realize with their own knowledge what CICO is! They need to learn the basics of Thermodynamic, and even the hard to grasp part like Entropy. They only need to know about Enthalpy! As an upcoming math and chemistry teacher, fit lifestyle offers a lot of ideas for things to calculate.   Like how much Energy do you need for curling a dumbbell. Is there an energydifference between free-weight-curls and the curl-machine? In chemistry, kids learn early about the concept of oxidation. there will be a comparison between the human body and a car. I will show them this experiment. https://www.youtube.com/watch?v=7Xu2YZzufTM and then burn some "fuel". they have to grasp the idea that everything we eat contains energy to fuel our body. They don't have to know how to properly meassure reaction energy but they have to grasp the concept of it, that we measured it with water and what a calorie means (they don't have to know that one calorie equals to 4,19 j/(gK) ) If they grasp both of those concepts, they can see how useful CICO is.  If their physics teacher is smart enough they will understand that acceleration consumes the most Energy in movement. So they will understand why HIIT is such a great method of burning fat. Since you are constantly accelerating. We as society need to push STEM-education in schools! We as people have to stand up to educate our children better. Most of the adults are doomed. But the children have a chance to break thorugh that vicious-cycle with education  If more people know about it, the less they will be screwed with Snake-oils, or with it-works wraps