Sorry DMD, I didn't see this until now.
"Eat to Live" is, in my opinion, one of the best nutrition books currently available. I approximate the Eat-to-Live plan, which is essentially a guarantee for maximizing disease-prevention and weight-loss from the food angle. The other primary angle is of course exercise, which is why this is such a great website/community.
If you haven't already, I would definitely try his 6-week plan.
As far as exercise and getting enough nutrients goes... this is usually a question of eating enough
food. Whole plant foods are as nutritious as eating gets; when you exercise more (especially if you want to increase muscle mass), you simply need to eat more whole plant foods at the same time. But if weight loss is your first goal (which is the way to go for reducing risk factors for certain diseases), then you would still want to keep your calorie intake moderate.
In my experience, it's very easy to get all the nutrition I need from a vegan diet. And by focusing on whole plant foods, I get to eat about twice what my friends eat!