I've been riding in the early mornings for decades. On the weekends at dawn, and during the week I do short (1 hr) rides before the sun comes up. I've never warmed up or eaten anything before riding in the AM, just getting dressed, getting the bike out the door is enough of a warm-up. While I probably am slower in the AM, I've always thought I got a better workout than riding later in the day (can't tell you why). As for nutrition, I just go by the old saying 'your energy comes from what you ate the night before'. Realize most foods won't digest to a usable form for (at a minimum) 1 - 1.5 hrs; I rarely ride more than 2 hours in a day, so eating just before a morning ride is useless to me. Water can be absorbed pretty quickly (like 20 minutes) so I just drink down a bottle before going out, and take 1-2 for the ride. YMMV Cheers.