You should aim to lose weight through a well chalked out plan for diet and exercise. First determine the number of calories you need to consume per day. For this, calculate your basal metabolic rate depending on your lifestyle. There are many BMR calculators available on line. While they are not 100% accurate, they give you a rough idea regarding the number of calories required to maintain your basal metabolic functions. Many online sites help you choose from a wide array of food items to build up your calorie need. You have to make a conscious effort to eat 3-4 small well planned meals spread throughout the day. This helps you burn calories better.
Since you can’t cut down calories drastically, you need to exercise to burn some calories. So if the net calorie consumption is less than need for basal metabolic function and burning of calories is reasonably good, you will start losing weight. You can get many charts online which show you how many calories you burn with a particular exercise. You can use this as rough guideline to help you with an exercise regimen that does not tire you out.
If you need pills to lose weight, then please ask your doctor about it. What may work for someone may not work for you. So, please go as per your doctor’s advice. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.