Concerning musculation, and as I see some fat on my hips and on chest, should I eat more calories, or my muscles can get calories from my current fat (which can be calories if I am not wrong) ? Is fat can be seen as a calories stock ?
There are 3 different options here. Depending on your main goal, how fat you are, and if you are a beginner/out of the gym for a while, you can either:
- Bulk (gain muscle with an appropriate caloric surplus)
- Cut (lose fat with an appropriate caloric deficit)
- Recomp (may only be possible if you are a noob or getting back into the gym)
Goal is gaining muscle while gaining as little fat as possible. Lift heavy. There is limit to the amount of calories the human body can actually put towards the process of muscle growth. Consuming more calories than that amount doesn’t lead to more muscle growth or faster muscle growth. Any additional calories will get stored as fat, so you still need to be conscious of your caloric intake. Here's a great article about bulking (and also cutting) the right way:
Goal is losing fat while maintaining your strength. Still lift heavy. You should definitely NOT just cut a bunch of calories and/or add in a ton of cardio, because although that may help you lose weight, the weight is going to be a combo of the fat and the muscle you want to keep. This needs to be strategic too to lose fat and not muscle. The same article as above about bulking and cutting the right way:
Goal is gaining muscle and losing fat at the same time. May or may not be possible. Noob gains are definitely a thing so you could very well be in a caloric deficit and build muscle. YMMV. Here you will (surprise) also lift heavy! Here's two articles I like that talk about recomping:
Yes, fat is actually that. When you eat more than you consume, the excess is stored as fat. There are different opinions that can be used as an answer to your question. I would recommend to start exercising and eating healthy. If you are fat, that means you are over-eating. So, start eating less and try to eat more healthy while exercising.
Burning (losing) fat usually does not happen fast, so this is not a sprint; it is a marathon.