Hllo dear u r 12 weeks pregnant In pregnancy u need 300 extra calories per day so u have to take healthy diet . when i was pregnant my weight was too low then i consult to my friend she suggested me pregnancy diet chart which u have followed in m sharing u that diet chart it ll help u . take Mother's Horlicks during Pregnancy. Mother's Horlicks, with 27 vital nutrients, is specialized nutrition for expecting mothers. Mother's Horlicks contains nutrients (like Iron, Iodine, Folic Acid, Zinc, Magnesium, Vitamin A, B6, B12 and D) which are known to help improve the birth weight of the baby.u can take oats .Oats r completely safe for pregnant women. as well as lacting mom ,oats contains considerable dietary fiber that helps regulate digestive system,oats r big source of Poatessiun &Iron .Take almonds pistico,walnuts,raisens dates.take all green vegetables such as spinach..beans,peas,beetroot,carrots take fresh fruits apple Mango,Banana..Mango,watermelon,muskmelon,chikoo,pear,Orange ,sweet lime, Pomegrate,cheese,paneer,tofu,buttermilk,curd.