Creatine can support muscle retention while losing weight. I would also try to get the majority of calories from protein. Still, discuss it with your doctor since I have no knowledge of how these approaches interact with your specific conditions.
I began tirzepatide roughly a month ago and have already dropped some weight, which is positive. The difficulty is that I have zero capacity for any sport or physical activity because of myalgic encephalomyelitis and postural orthostatic tachycardia syndrome. This combination gives me basically no exercise tolerance and the illness is fairly new, which is tough. I used to do plenty of weightlifting, cycling, running, skating, skiing and swimming. I'm hoping to hear from others who also have these conditions or from movement specialists. How can someone on a GLP-1 protect muscle when exercise is impossible? Losing weight should help my future quality of life, yet it feels especially difficult when movement is so limited.