thank you for your query.... as per your information, your body mass index (BMI) is just about 11.5 whereas 18.5-24.99 is considered normal...you are severely underweight at present...to attain a normal bmi, you need to gain around 20-25 kgs...otherwise you will face many health related disorders in the upcoming years... you have also said that you take only 2-3 rotis per day... you should increase the food intake immediately... take 3 heavy meals per day comprising of proportionate amount of carbohydrates fat and proteins... also take 1-2 light meals... this will help for sure... my advice will be to consult a dietitian for a diet chart.... feel free to contact me anytime for further queries... regards