I have not been treated for cancer but was a primary caregiver for a family member about 2 and a half years ago. It’s very important to keep eating, especially protein during treatment. Find out which foods are most appetizing (not junk or processed foods) and have more of those. My family member had a protein shake once a day. She also had a prescription to reduce nausea. It helps when others eat with you and encourage you to eat just a bit more. Talk to a dietitian specializing in cancer treatment. There may be tips. Is there a particular time of day when you can tolerate food more than at other times? Perhaps reframe your thoughts about eating as your contribution to the treatment process and focus on the positives. From my experience a positive attitude can be the most important factor that you can bring to your health. All the best.