Your body won’t release fat stores if you lower calories below what it needs and increase exercise. It will slow your metabolism to compensate and store every spare ounce as fat. If you continue lowering your calories, it will continue lowering that set point, til you can survive off nothing and store fat on anything.
You will lose more body fat eating protein and fat (don’t eat protein alone) than not eating AT ALL. To lose weight fast eat all you want but nothing but meat, eggs, healthy oils, mayo, butter and half an avocado a day (you’ll need added potassium). Keep the calories high and the fat percentage high, at least 65% of calories. Adding in green vegetables & some cheese will continue weight loss but at a slower pace.