2023 will be my lowest running mileage of the past 8 years but I've done more strength training in the past three months than I've done since I was in high school.....and that is not saying much!  I'm 20 lbs heavier than I was 2 years ago and wear the same clothes and feel like I have energy and explosiveness.  I'm still not strong. I'm working on getting back to eating better with less sugar and carbs and more healthy protein and vegetables.  I'm going to suggest that the mental clarity aspect of dieting has more to do with improved sleep.  I tend to sleep better and need less sleep when I'm eating well.