Interesting question. We also try to avoid sugars, except for fruits and dried fruits for the most part. Although as you will find out from people that follow McDougall, he allows some sugar (also salt) if that is what it is going to take to get people to change their diets to a whole food plant based diet. That certainly seems to make sense.

A search on DrCarney.com for the word "Sugar" gives the following results: 

https://www.drcarney.com/search?q=sugar

Hope some of those are helpful to you! :-)