Basis your BMI which is 15, an ideal weight for you should be somewhere between 52-58 kg. Diet management has been proven to be beneficial for maintaining a healthy weight. Eating calorie dense foods thinking that it would lead to weight gain is not correct. You must:-
a) Set your metabolism levels right by following a strict dietary regime and setting your body clock right
b) Include foods that are nutrient as well as calorie dense
Next Steps
Include things like almond and banana shake in your diet, add dates to it. Add roasted sesame seeds to your vegetables. For more action points on the correct combinations of food that are nutritionally dense, you can contact me on direct consult or visit me to get a customised diet plan suiting your needs.