Vegan....no more (20 characters)?!

Pizza is probably not the best thing to start out with. If his body isn't used to lactose, it will probably be difficult to digest.

From my personal experience, it's not always an easy switch. I was a vegan for several months when I was 15, but started including non-vegetarian foods into my diet again when I returned to street life. The first time I ate mayonnaise, I thought it was disgusting. It was too rich for me after so long without dairy-products, and made me feel queasy. I remember trying bacon for the first time and I was overwhelmed by how chewy and greasy it tasted. I didn't feel well after trying it, and couldn't finish it.

That is just my personal experience, and everyone will likely be different and have different reactions. Your husband might want to see a nutritionist or his doctor for a consultation. I recommend it any time you make drastic changes to your diet.

It's been 7 years, so his body has definitely stopped producing the enzymes needed to digest meat by now.
He's not going to feel to good... I can guarantee that.

Something healthier would make his body reject the meat and cheese less.

his body MIGHT reject it. By Puking or Diarrheaing

naaa itz private

i reckon for at least a month he will feel a bit light headed/dizzy due to the meat hrmones entering him in a long while
after he should feel fine

every one is different but i'm sure he will feel sick. your right to want him to do it gradually.

No, he won't get sick. He's an omnivore. His body is capable of eating meat whether he choose to eat it or not. Pizza is pretty greasy; that might upset his stomach. But if he doesn't "pig" out on meat, milk, etc., he'll be fine.