HI Trav, thank you for reaching out. We are in similar ages so I'd like to give a perspective from my angle. I also fast for health reasons as I don' t need to lose weight anymore. Long ago I used to take protein shakes which easily put me out of ketosis as they quickly digest and turn into glucose breaking fast. Protein is critial therefore I consume them from bioavailble sources including all essential amino acids. My prefence of consuming protein is after workout from ketosis and recovery perspective. After workout muscles need glucose and amino acids to recover. Thus they use sugar and protein much better making the body more insulin sensitive. Insulin sensitivity is a health indicator preventing us from metabolic disorders like type II diabetes. 18/6 intermitten fasting regime is very common and doable. So in my experience doing the exercises two hour before or two hours after meals provided me a better insulin profile. I hope this perspective helps you personalize your regime. As there are so many other factors it is not possible to provide a prescriptive guidance. Sleep is critial too to keep the body insulin sensitive.