I am sorry about your upset stomach. This is a common issue in patients going through radiation treatments. What you are worried about is very important, sufficient nutrition in your diet is necessary to help your body recover and maintain health. At the end of the day, you will have to experiment to find the right nutrition plan for you.
If you can, meet with a nutritionist to develop a specific plan for your diet and make sure you understand the calories, protein, vitamins, etc. that you need as well as food options and how much to eat.
Here are some general suggestions that may help:
- try eating snacks and small meals throughout the day instead of a few large meals
- make sure to eat foods high in nutrients (high in protein or calories, such as nutrient bars, ensure, nutrition drinks, milk shakes, cheese, fruits, peanut butter, nuts, crackers, and juices.) and stay away from foods with little nutrition such as junk foods.
- drink dense fluids such as milk, milk shakes, and juice.
- when you feel good, make sure to eat
- prepare food that is colorful and appealing to the senses.
- try different seasonings
- bland foods, such as crackers, broth, and rice, may be easier to digest.
Depending on how you feel and the severity of the side effects, you may want to talk to your doctor about medications that may help alleviate an stomach upset and prevent weight loss. Here is a link to a list of potential medications your physician may prescribe for lack of appetite:
http://talkabouthealth.com/what-medications-might-be-prescribed-for-lack-of-appetite