Absolutely nothing will improve your performance like riding with a fast group. This is repeating what several others have said on this thread. All the hip ideas like trainers, training plans, nutrition, are secondary. Ride with fast groups and you will be come a more skilled, fit and efficient cyclist....not to mention a more attentive, disciplined and faster. Eat healthy and don't be scared of sugar and/or fast foods. To an exercising athlete, you'll burn it off quickly and it will provide energy when you need it.