You may have difficulty eating normally for several reasons.
Any illness can cause tiredness, mood changes or loss of appetite.
When you have cancer these may be caused by the effects of your illness itself, anxieties or concerns about it or the effects of your treatment. Loss of appetite is not uncommon and sometimes it seems to happen for no apparent reason. Your appetite may come and go, so make the most of the times when you do feel like eating. You may find it easier to have small meals and snacks instead of trying to eat a large meal. The amount of food on your plate may, in itself, reduce your appetite.