Hello,
I am really sorry to hear of your difficulties. I can relate so much. I have always been super fit and athletic. I am hyperactive and need to move. But after degenerating from spinal cord compression, I have difficulty even walking fast.
That being said, probably about 80-90% of our overall health/physique is dependent on our eating habits/type of foods we eat. Eating clean unrefined foods is vital (little to no processed foods, no gmos, antibiotics in our food, etc.) But one thing that can really help with keeping our physiques in shape can be intermittent fasting.
There are many methods, but all help to lesson the load on the body by allowing a cleansing time, and limit the amount of hours our bodies have elevated blood glucose from eating.
I usually don't eat after 8pm and then don't eat again until about noon the next day.I have 6 kids and no one believes I even have one.
Try a search on intermittent fasting. It may help.
Good luck.