Welcome to the gastroenterology community! Problems could include malnutrition, bowel problems, cancers, thyroid problems. There are so many different things that can cause this.
lack of appetite due to gastritis,pancreatitis,gallbladder attacks these are some of the reasons why I have lost weight when I was not trying. All pertaining to the digestive system and it could be many more reason. Including having a serious illness.
Thank u for reponding to my question