Maintaining muscle on keto

I followed the keto plan for a few months last year and I felt wonderful and lost several inches in my thighs, waist, and abdomen. I have been a group fitness trainer and RN for most of my life and I work out at least an hour daily. I felt like I lost muscle last time and I looked super thin in clothes but felt like I looked skinny fat. Do you have any suggestions on how I can do keto but still maintain my muscle?  Thanks. Nerissa