you have your budget set so i would recommend the Trek 1.1 for example, retailed at 740 usd. to chose the correct size is important, for that we need to know how tall are you (other measures like inseam are also desirable but with height you get a first general idea of frame size needed) For nutrition you should never ever ride without having your breakfast, or your lunch, or dinner if you are training at night. On longer rides you need to add a banana, or a power gel on your pocket, carry water or other fluids in your water bottles using one or two of them dependending on the distance you are doing and the climate,