M.C.
Go you! Great call! We made the switch about 2 1/2 years ago, after DH's dr threatened to put him on meds for high cholesterol. Instead, we totally changed how we eat--mostly vegetarian, no processed foods, lots and lots of fruits and veggies--it's actually a lot easier than you think, and you'll feel GREAT. I lost 10+ lbs (DD was 8 mos old at that stage, and I hadn't lost all the baby weight--I ended up weighing 10 lbs less than I did BEFORE I became pregnant the first time!). DH lost 15 lbs. DH's cholesterol dropped 80 pts. Perhaps most dramatically, I had gestational diabetes with my first pregnancy, and NOT with my second--my dr says this is almost unheard of, and calls me a "rock star" every time I go in (I'm due in 4 weeks!). I've only gained 25 lbs (from my 10 lb down starting point) with this pregnancy, so I'm sure getting back to pre-prego weight will be much easier.
To make the switch, we stopped buying pre-prepared foods (basically anything in a box or freezer case)--shop the perimeter of the grocery store (produce, dairy, meat/fish). It really doesn't have to be fancy--broil some fish, boil some rice, steam some broccoli, you're good to go. Lunch today was scrambled eggs, (natural, real) cheese and crackers (Triscuits good, Wheat Thins bad), and carrot sticks. My general rule is that if I can't fully explain how God put it here on earth, I don't eat it (that means that, when you read the ingredient list, you should be able to pronounce and explain everything on it. No chemical names!). When we buy things like salsa, for instance, I get the one that reads "tomatoes, onions, peppers, vinegar, spices." Organic brands are more likely to do that for you, but we're not strict about organic, just about knowing what we're eating. It's also turned out to be a lot cheaper for us. Drastically cutting down meat consumption helped with that--there's a reason poor countries subsist on rice and beans, but there are lots of tasty ways to make them.
As for family support, we were lucky in that DH was motivated by health concerns--he really didn't want to go on more meds--and we made the switch just as DD was starting to eat table food, so she's never known any different. But it's all what you're used to. DD, at almost 3, LOVES eating "little trees" (broccoli), and DO NOT get in her way on black bean taco night!
If you want recipe ideas, feel free to PM me with your email address, and I can send you a bunch of recipes in a Word file that I put together for my sister last Christmas. Lots of kid-friendly vegetarian recipes. Good luck, and congrats on getting your fam healthy!