Lifehacking --> Quantified self
Knowing your calorie count helps you understand where you may be overestimating your exercise and underestimating your intake, which is a common problem when people try to lose weight. As you gain more experience, the data itself becomes less and less useful.
I'm not convinced that ever-more-granular access to data (such as precise micronutrients) makes people any healthier than those who don't pay attention to them.
All things in moderation. Including moderation.
You've never had an ECG done?
We already do it. We get hungry, so we eat. When we are very hungry, we eat more. When we are not very hungry we eat less. That is a quantification of our life to an extent.
To me, life hacking is expanding that understanding. I get distracted, why? Do I need to be distracted because the distraction is doing me good? I don't want to be distracted because I have things to do. If I can do something that gets me what I need from that distraction more efficiently I should do it. If I can't, and I still have too many things to do, I should get fewer things to do. Is the distraction a result of something external (poor diet, poor sleep, poor exercise)? Could I correct that external problem and then be less distracted?
For me, it's not a matter of turning into an automaton. It's a matter of agency. I want to be in control of my actions, which means I need to understand what is going on in my life. If I get distracted, I want that to be because I allowed myself to become distracted because it was in my interest.
A healthy balance is optimal, but if I want to pull an red bull fueled all-nighter, that's fine too. It just means that I will throw off my routine and ruin my sleep for a period. Sometimes that tradeoff is worth it, but you can only make that judgment if you're aware of the consequences and alternatives.
You can put nitrous on your car, and while it might damage your engine when used for prolonged periods, in short bursts it will increase performance. Understanding the risks and damage it can do can lead to making more educated decisions on when to use it. Otherwise all we're left with is feeling and panic.