500 calories would probably put your body in a starvation mode and not be good for you long term. I do a lo carb hi fat diet (LCHF) and find it works for me very well. Go to https://www.dietdoctor.com/low-carb for great lo carb recipes. I make them and they are not only delicious, but help me to stay off the sweets and hi carbs painlessly ! Good Luck....I am back on a stricter diet after the inevitable holiday binges.