I haven't read the book, but a soy zone diet sounds more to my taste than the Atkins or the zone diets. My approach has been to burn a lot more calories through exercise while trying to keep my diet the same -- it's hard, I get hungry after a bike ride -- and I do find that a tall glass of soy milk will keep me sated for longer than a bunch of carbs,
although I've heard you burn carbs better right after exercising.
The message I took away from that article was that the real problem is that Americans eat too many calories, particularly sugar and carbs,
and we should focus on that. One way is to get more protein and fat,
but you really ought to eat quality protein and fat. I was a vegetarian for 10 years but lately I have been eating fish again, because my reasons for becoming a vegetarian were health related and a bit political, not related to moral qualms about eating critters. I think the healthiest diet is the old Japanese diet (before they started eating the McDonald's diet over there): fish and rice. Substitute tofu and soy and I think that's fine, too.