Also, I think 800 calories a day is very little, 1000 is enough to create a deficit of calories. I like to eat a variety of foods, lots of chicken, eggs, pasta and rice instead of carbs, and lots of vegetables. This allows me to maintain a healthy diet that helps my body build muscle during exercise. Also, if you go in for sports, I recommend you a protein shake, it will also help you a lot. In your case, you may not be getting the minerals and vitamins you need, so you need to add them for best results. I advise you to add them to your diet so that there are no violations in the work of organism.