"not as fast", well, a well-configured touring bike vs an adequately adapted "true" road bike in commuting service there will be very little difference in commuting speed, but the touring bike will be more comfortable, versatile & robust. I'm thinking of a true touring bike with somewhat relaxed geometry, relatively long chainstays, relatively stronger frame & wheels, and front & rear racks for better load distribution. This is a much better solution for loaded commuting than adapting a "race-oriented" road bike. Of course there is a more or less continuous spectrum of bike types between racing-style road bikes and true touring bikes, but you get my drift.