If you actually look around here, there are contributors to a lot of websites that show this "proof" you are searching for (Sheldon Brown, Ceya, Tomity are three good examples of people with a wealth of knowledge on fixed gear. Some of the frame builders in here may be able to shed more light on your quest too)

Bike Forums SS/FG = Pudding, look deep. The proof is here

Read through the threads. There is a variety of non-anecdotal info - and your question has come up before. Plus, the Search is half the fun.