Hello, You are 45kg and 5ft 3 and want to gain weight. You have been taking Ensure plus drink and Apetamin syrup to help gain weight. Apetamin syrup is banned in many countries. It can interact with alcohol, grapefruit juice, etc. It can interact with antidepressants, Parkinson’s disease medications, and also with antihistamines. It causes side effects like tremors, dizziness, sleepiness, irritability, blurred vision, liver toxicity, liver dysfunction, etc. Ensure plus also has side effects like constipation, diarrhea, vomiting and nausea. It should be taken as a nutritional supplement else it can cause weight loss as it does not meet all nutritional needs of the body. To gain weight. you should get on a regular eating schedule. Make a chart so that you can eat 4-6 times a day. Target to eat high calorie food, nuts, dried food, take food cooked in heathy oils and fat, starchy meal and wheat germ, flax, bananas, pumpkins, high protein diet, cheese, beets, avocados, wholegrain wheat and deserts. Do not hasten, gain weight slowly and steadily. Get connected to a personal trainer. Do aerobic exercises. Stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician