there are many specialized pregnancy diets out there. Pregnant women need certain amounts of different nutrients (such as more folic acid than the average adult woman/human), so they often need a specialized diet. because i don't like vitamins and don't want to take them--it's likely that i won't want to take pre-natal vitamins. Therefore, it's important for me to understand what nutrients my body needs and how to get them from foods such that i don't have to take the vitamins.
similarly, specialized pregnancy diets may help alleviate various 'pregnancy symptoms' such as nausea, bloating, edema/swelling of joints, even back pain and head aches--and prevent various risks such as hypertention, preeclampsya (sp?), braxton-hicks contractions (early, false labor) and pregnancy-onset diabetes.
There are many types of specialized diets out there. In the book i mentioned above (the gentle birth), the midwife recommends that it be soy and gluten free and rich in whole foods (it's not necessarily vegetarian). Looking at the vegetarian pregnancy diets, there are certain recommendations there for meeting the nutrients needs of both mother and child.
there is also a specialized lactation diet.
The reason that i want to have this specialized diet before the pregnancy is two fold. First, we all know that it's difficult to change dietary habits. for many, it's difficult to go vegetarian, or to let go of soda or sweets--right? Why do we expect that when we suddenly become pregnant, it will be easy to let go of 'comfort foods" such as whole-wheat bread (gluten!)? Many women i know study pregnancy diets, but once they get pregnant, they simply rely on their vitamins. It's hard for them to change eating habits for their pregnancies, because they didn't do it before hand. By giving myself a year to 'settle into' a pregnancy diet, i'll consistantly have a pattern of eating that is 'best' for my pregnancy already in place so that when i'm pregnant, it's no struggle to change or add things to my diet--basicly, i'll already be in the habit.
the second reason for doing it a year in advance is to 'build up' a supply of nutrients in the body. it's true that roughly every three months the body has let go of all stored nutrients and replaced them with new (sometimes, it's even a daily process of getting rid of excess and what not), but it is possible to 'build up' a store of nutrients over time and to help the body maintain that store over time. In traditional cultures, when a woman is preparing for her wedding (and thereby her first pregnancy), her diet six months prior will be rich in folic acid, iron, vitamin A--to mention a few. Over the course of the 6 months, the body begins to store and utilize these nutrients differently, in preparation for pregnancy. many women notice that their fertility cycle changes, becoming stronger, healthier, more predictable--and therefore ready for pregnancy. so it may be that the body is preparing for pregnancy whereas when on a 'regular' diet, it may be more likely to have a lighter cycle, that may not be ovulatory.
So, since it will likely take me 3-6 months to adapt from my 'normal' diet to my 'pregnancy' diet, that gives me 6-9 months prior to pregnancy to make sure that i'm getting my nutrients and getting enough of them to feel comfortable. I'm setting up a basis for my baby's health well before it's even concienved, and then able to maintain that throughout the pregnancy so that the baby can develop in a healthy way.
i know that to some people, this seems extreme, but i'm also already planning on specialized yoga and exercise routines that will work throughout the pregnancy and will be adaptable for after the birth (where the child can go with me or where i must go alone--which makes nursing on cue very difficult to an extent--so it's another issue to think about seriously).
most people i know who go to birthing centers or hospitals seem to have fine births, but for me it's just not an option unless there is medical need. since i was 13 yrs old and realized that i may, someday, become pregnant, i've always wanted a home birth--with or without a midwife. It's likely that my first birth, at least, will be with a midwife and perhaps others after will be without. we'll see though.
i guess it's just one of those intuitive things. I think that this way is the best way for me, and really always have. i'm certainly not against women making other choices, as long as they are informed choices.