@gweiman
I have SMM and am 65. I’ve lost 20 lbs since diagnosis a year ago. Partly intentional as my readings suggest weight does play a part in this. But I also struggle with atypical fatigue that I’m convinced is related to SMM. My MM specialist said many of her SMM have fatigue. I wonder if you are getting enough protein which is necessary to build muscle and we know muscle burns more fat. Maybe your doctor could advise on the protein you need too much can be hard on kidneys) or make a referral to a dietician? I do think movement and maintaining average weight are critical to keep disease progression at bay. All the best.