Hello dear, Thank you for your contact to health care magic. I read and understand your concern. I am Dr Arun Tank answering your concern. No, you can regain the weight but it takes some times. Typhoid causes a state of severe catabolism that is why the weight is severely reduced. Taking diet after convalescent period is very important. You should not take a bulky diet at once, taking a small frequent diet is good. Typhoid causes small intestinal ulcer if you eat bulky diet it can be perforated. Perforated ulcer can cause many complication so better thing is you have to avoid it. You have to start gradually daily exercise. It will built up the muscle mass and helps regaining your weight. I will be happy to answer your further concern on bit.ly/DrArun. Thank you, Dr Arun Tank Infectious diseases specialist, HCM.