our hormones affect our bodies and it even affects our taste buds and our cravings. sometimes our bodies crave potassium so we want a banana, sometimes iron so we crave meats. but when you crave something strange, like drywall or dirt this is called pica. if you think you may have pica please bring it up with your doctor and do some research on the topic. Best if you can avoid giving into temptation. For example there was a celebrity that craved bone marrow...she never wanted it before or after her pregnancy, but couldn't get enough of it during her pregnancy.
hopefully you are just craving chicken when chicken wasn't on your menu before. there is nothing wrong with that and its very normal. i am not a chocolate lover but could eat a chocolate bar a day this pregnancy.
When your NOT pregnant it can mean your body is lacking a certain vitamin I've been told. I'm not sure how true that is. I know I go thru stages where I can't get enough raw sliced tomatoes. I don't think it's harmful to crave things unless they are not good for you and you just can't stop eating them.
Nooo... Everything changes when you're pregnant, including cravings. Many of my favorite foods have been my least favorite during my pregnancy and things I've never eaten before or didn't like, I love now.