Welcome to Healthcare Magic forum. Your basal metabolic index (BMI) is 19.25 which is on the lower side of the normal range. As per your age group and activity patterns, you should be taking in anywhere between 1700-1900 calories in a day. Studies indicate that a 2000 calorie diet with mild exercise is healthier than taking in 1700-1900 calories.However,this is not the time to worry about such issues and ideally you should be concerned with remaining healthy and fit in the long run. A nutritious diet and exercise are keys to staying healthy in the long run. Exercise is an important component of your daily regimen as it has a host of benefits including prevention of diseases such as diabetes
, obesity etc. A healthy adult should ideally have atleast 50 minutes of exercise 5 times a week. The amount of exercise not to gain weight however would also depend on your dietary habits and medical condition. As of now, concentrate on your exams and all the best!