Here is a response from Dr. John McDougall who has been successfully treating lifestyle diseases, including heart disease, cancer and adult-onset diabetes, with a low-fat vegan diet for decades:
This article published ahead of time in the American Journal of Clinical Nutrition was by the same authors as the vegan osteoporosis article I published in my June 2009 newsletter. The article I reported on received little press worldwide and showed results very favorable for a vegan diet and bone health. The McDougall Newsletter - My Favorite Five Articles Recent Medical Journals.
This study showing negative effects of a vegan diet was a meta-analysis and these kinds of studies are notorious for showing bias and are easily manipulated by the choice of studies included or excluded in the analysis. There are many other criticisms that could be directed to this publication but the most important question to ask is why did this article get so much attention and the other one by the same authors published at the same time received almost none?
One fact you should know is the meta-analysis article suggesting vegan diets may be bad for the bones (slightly lower BMD) was funded by a AMBeR alliance incorporated in Malaysia, which owns Amber F&B Nutrition Sdn Bhd, a dairy products producer and wholesaler.
You can write the authors at: firstname.lastname@example.org ask your questions about the studies and why the one paid for by dairy money received so much world attention.
Reference to financial ties: Amber Alliance Sdn Bhd acquires F&B Nutrition Sdn Bhd - Nov 15, 2006 - Deal Snapshot - AlacraStore.com
It is very interesting to me that most anti-veg articles can be traced back to meat/dairy producers. There is a wealth of information now that proves without a doubt that vegetarian/vegan diets are perfectly healthy, and mountains of research from reputable people like Dr. McDougall, T. Colin Campbell, Dr Neal Barnard, Dr. Dean Ornish, and John Robbins [to name a few] who back up everything they present to the public with a slew of scientific sources so that you can do further reading, if you choose.
I also just wanted to say, based on my own experience, that veg diets do NOT require any special planning. Simply eat a wide variety of whole foods, cut the junk, and you are good to go. It isn't difficult or complicated at all.