Chemotherapy drugs can affect your appetite in so many ways. Some people only experience side-effects briefly or temporarily, others may be affected more seriously and really struggle to enjoy their food.
Chemotherapy can affect your sense of taste and smell, making you much more sensitive to strong smells and distorting tastes so everything tastes the same or is tainted with a metallic taste. In addition, the treatment may make your mouth and throat sore, and perhaps sensitive to hot and cold foods and drinks. Anything that affects your ability to swallow can make you nervous about eating; nausea and the effort of being sick can also be exhausting.