Hi @brad78 I posted a discussion about side effects of radiation a while back. here is the link: https://connect.mayoclinic.org/discussion/radiation-side-effects-when-will-they-ever-end/
Typically during and after radiation one can only tolerate a few foods, primarily soft or liquids for a while. I had broth, soft eggs, custard, porridge (oatmeal), cream of wheat, Ensure, and similar foods. Nutrition consisted of whatever could be tolerated. Regaining protein and calories was the primary goal.
You will find foods you can tolerate, perhaps foods you never cared for suddenly become favorites. Your taste will likely change. Swallowing may become a challenge. In fact it still is for me as I am often the last one at the table to finish. It's a "new" normal we all get to.
Don't fret about these changes. Don't be surprised about them either.
You may have an easy time of it, or perhaps not. We all are individual when it comes to this.
But to summarize, Eat what you can, when you can. Don't worry about a balanced diet. There will be time for that later. And keep active even if it's just a slow walk around the house.
I know this all sucks. Feel free to contact me anytime. I usually check this site at least once per day. I wish I could walk you through this, I really do. But you will be okay in the end and perhaps better. There is a saying something like "Scars have better stories than tattoos".
Courage.