Its not a healthy way to lose weight, you should eat about 4-6 small meals a day. Don't go under 1200-1400 calories and do soem exercise. Try a non mixing diet look up no pain feel great diet on the net and download the PDF Certain foods do not digest properly at the same time. Such as you should eat fruit separate away from other foods. Eat protein with veggies and salid, and NO CARBS. and You can and Carbs with veggies and salid but no protein. When you eat this way your body digest he food better and many lose weight. I am doing it and I am down 26 pounds so far in 9 weeks.
No one can say without knowing all the variables. Calories you burn (activity) minus calories you consume are the key. But the calories you burn are determined by exercise, current weight, and metabolism.
500 calories a day is kinda light, and your body will adjust to the reduced intake making it harder to lose weight. You might want to go with 1500 calories a day and increase your exercise. It will be easier to maintain for the long term.