Your weight definitely can be a bit different during a day or a week, but the main word is a bit. If you ate too much on friend's party or ate spoiled food and got poisoned, you will find it on checking your weight. However, sometimes people having a usual life, usual diet lose more than 5% of their weight. It is a good reason to check health.
Losing appetite is the side effect of clinical depression. Often it is going together with a bad mood, inability to take decisions and sleeping problems.
Basically, it is too active thyroid which starts to produce more hormones than your body needs. Often side effects are not only in losing weight, but also in raising the heartbeat, problems with sleeping and disorder of thermo balance of the body - you always feel hot.
This is an autoimmune disease, when your body is not capable to digest gluten food and irritate intestinal wall. Usually, it goes together with vomiting and diarrhea, that's why it is similar to intoxication. However, if your intoxication is far too long, try to check it out with gastroenterologist.
Yes, it is also leading to losing weight at some point. Your body is not able to digest glucosamine and gets rid of it by urinating. So, that's why you always want to drink and go to the toilet. Check out your blood glucose test and ask your therapist to clear the results for you.
The pancreas is producing special material which helps to digest the food. However, if it is not working or not working well, you may get fitter. Other side effects are pain in the abdomen and problems with digesting fat food. Check everything out with your gastroenterologist.
Of course, it is not the whole list of the diseases where side effect is losing weight. However, I hope this article will help you to understand that sometimes losing weight isn't a point to be happy, but the reason to go to the doctor and check your health in an early stage.