There are people so obese that it is life threatening, and even then, they are cautious about minimum calories. A 500 calorie diet over an extended period gets treated by your body as a fast. It will burn muscle. It will lower your metabolism. It causes coordination problems. People in famine make more mistakes and have more accidents. When you finally end the famine, your body has learned that there will be feast and famine and people put on more weight than before the famine to prepare for the next famine.
Bottom line - Your body does what it wants to do, not what you want it to do.
History shows it. Besides which, you should be incredibly hungry all the time. If that's what you want to do, try it. There are no laws against it.
Just don't complain after three months off the diet if you weigh more than before.
Experts that have no money-making incentive agree that 1000 to 1100 calories a day of mostly vegetables and added lean protein will get you to proper weight in a reasonable time. It took a long time to put on the weight and trying to lose it too quickly causes loose skin, bad attitude, often nutrient problems, and in some cases your own body can poison itself. Pollutants from the environment and some chemicals in food build up in fat and burn the fat quickly and the body cant clean itself inside fast enough.
In the long run, to maintain a healthy weight and optimum nutrition you should be eating healthy diet. If you start that way on controlled portions and cautious about "bad" food and just start on lower calories, it is much easier to maintain the weight loss. If you start a weird diet it is harder to change to a healthy one.