Pffft, training. I eat a couple of pies, washed down with a chocolate milk; does that count?

Just do a general strength and conditioning program and ride more. The more you ride, the more bike fit you will get. You can get carried away with fitness and losing weight, but that won't necessarily make you faster; hell, look at Marshy compared to all those skinny fit riders.

PS. If a fat bastard like me can get around the track for 5 laps, the average person should have no problems.