It will take certain nutrients from you but your body doesn't store all nutrients only a few it keeps in stores like calcium... And it will take its calcium from you making you deficient. This is true. But other vitamins and most vitamins your body doesn't store
Well you can always get vitamins.. if you from uk you can get free vitamins from a chemist
It NEEDS proper nutrients... I mean you are developing an entire human with bones and nails and a brain with its synapses and currents as well as muscles and skin and heart lungs and all other organs. A fully functioning person from a strand of DNA from the father and a strand from you. It is basically a couple cells that develops into a functioning person... You develop this over the course of nine months due to your NUTRIENTS you intake. So yes proper nutrients help the development correctly. At least take your prenatals if you don't eat so healthy and know whatever you are eating does contain some kind of nutrient...
Also if you eat super poorly like chips and fast food and coke all day everyday or other equally unnutritional good for nothing food that tastes good.. You can easily get gestational diabetes which can result in many other issues like a overly large baby due to fat which could result in a potential c section..
Your baby will pull the nutrients that he/she needs from you, making you become deficient in certain vitamins and minerals. Def not worth it. I barely upped my intake of calcium and for 4 weeks towards the end of my pregnancy I craved string cheese like no other. It was terrible. I think I finally got it regulated, but I don't suggest it!
It won't get proper nutrients