"Don't fast for more than 72 hours cause your body will start burning muscle", they said
No. It doesn’t. It won’t. When you fast for more than 12 hours the body starts burning fat, and it burns fat until there’s no more fat to burn. That’s when it starts burning muscles and organ tissues. So, yeah, only a few know a normal body has 100,000 calories of fat = 50 days of survival if you fast. Look up ketosis on google and you’ll know why you feel dizzy, you feel dizzy because your body is used to burn glucose instead of fat and it becomes a sugar addict. When your body gets used to burning fat instead of using glucose as its main energy source, you stop feeling dizzy because there’s plenty of energy in it.
The only reason why your body likes glucose so much it’s because it’s instant energy, unlike fat, which requires more effort to be burned.