Any time I plan on training twice a day, whether it's 2 running sessions or running and weightlifting in the same day, I find that my nutrition is low/poor. My first training session (usually running) is fasted, and I feel as if anything I eat before the second training session makes me feel sluggish and heavy. Should I just eat the majority of my calories after both training sessions? Is it safe to do 2 sessions on very low amount of calories (or even fasted)?