So you are suggesting only doing one or the other at a time?
What I am saying is using cardio to increase calories out, over time will cause compensation via ones metabolism. So in the long run, its just shooting ourselves in the foot. The same with purposely reducing calories in (I am talking about not eating to satiety here), also causes compensation.
If we look at
Calories in = Fat Storage + Calories out
-> Fat storage = calories in - calories out
That equation is over simplified. Using 'the first law of thermodynamics' to justify using this equation as a primary rule to losing weight is a strawman put up by those who want to sound scientific (justification used by big profit corporations such as Coca Cola, just drink that coke and reduce calories elsewhere). Hence eat less (calories in) and exercise more (calories out).
Firstly it is ignoring that we are living biological systems. We are not closed mechanical systems, and there are more variables involved.
Take hormones for example. There are leptin, cortisol, insulin etc..
I guarantee you, if I have a person who eats X amount. Then I reduce his X amount for 2 months, while injecting him insulin, he will gain weight. From that already, we see
Fat storage != calories in - calories out
Its a huge subject to cover, but to cut it short, it is
1. Controlling your hormones, insulin being the major one by (what you eat and when you eat > how much you eat)
a. Changing the dietary macronutrient ratio.
b. Fasting
2. Increasing ones metabolism via muscle gain (e.g. by weight/resistance training).
There are other variables (such as sleep and stress to control cortisol) but those two pointers alone will make a significant impact.
