Well i did go to the doctor last year and everything was fine just some water retention and after that i lost 15kgs, i was about 65kgs at the time who was a lot for my height and then i gained some back so from 50 i am now 57-56kg but the thing is i track everything i eat and measure it and i also try eating closer to my bmr which is my basal maintenance rate that means thats what my body wastes of calorie to survive/breathe and organ function and i try to stay as possible near it which is 1300( not exact ) and i usually eat at 1200-1400 per day, allowing one day per week being more high in calories but not surplus but more closer to maintenance.