As an example of some contradictory data, there is a cold virus associated with much higher rates of obesity:

https://www.sciencenews.org/article/obesity-children-linked-...

Also, the questions asked generally here "How can society as a whole have less obesity" is different from the one you are answering: "If I am obese, what can I do to improve my health."

I'm assuming you know we excrete unused chemical energy, so we aren't a closed system in which the CICO principal would be more deterministic.