Moderate intensity cardio is not helping you burn fat. I had read this before, but I was shocked when I went in to get a calorimetry done and tested it myself.
A calorimetry test reveals exactly at what exertion level (how fast your heart pumps) you burn fat versus carbohydrates. The results might surprise you.
The gist is this: as you work up your cardio zones, your heart needs increasingly easier access to energy and switches from burning stores of fat (less accessible) to carbohydrates (easier access). This means that there is a sweet spot of heart rate where you burn fat.
For me, the fat-burning zone is in the 80-100 bpm range (which is very low - think walking in the park at a moderate pace).
After 112 bpm, I stop burning fat completely!
It's likely you are hovering in zone 3 (mid range) and you end up wired but tired without impacting your fat reserves. This zone keeps you in a state of stress without improving your VO2Max (you need zone 4 and 5 for this, so really an all out I-am-dying-here effort for 5-30 seconds, recover and back again) or getting the fat burning benefits of zone 2 and below.
To top it off, the more you increase your cortisol the more your body feels stuck in fight or flight and ups the need to store fat and reaches for easier access energy (muscle & carbohydrates).
You need to do progressive load, which means increasingly heavier weights.
I started strength training as a way of recovering from knee surgery and it is a game changer. Belly fat really goes away and I have never had this muscle mass before in my life.
Don't fall for the weight trap! Muscle is a lot heavier than fat so your weight will be higher, but that doesn't mean you are fatter 😉
It feels like you are not working out, but you are!
You can monitor your heart rate or use perceived exertion (you should be able to talk but it's not super comfortable).
(For example) go all out for 10 seconds and then rest for 30/40 seconds. Repeat 4-5 times.
You can build up to this.
This will boost your cardiovascular system and capacity without skyrocketing your cortisol.
You will 100% notice a difference in your energy levels, you will have stronger leaner muscles and lower fat percentage.