What Are The Do's And Don'ts For A 3-4 Weeks Pregnant Woman ?

Hi, Doc my wife is pregnant , it is her 4the week now and I m very excited about the baby, but I m also worried about her health. I m just curious what extra care she need to take to keep herself and the baby healthy, I m little concerned because she is finding herself in a hard position right now. She isn t able to take good care about her diet . She wishes to eat something healthy, but couldn t eat any thing properly, her diet is really disturbed, she always find some kind of foul smell in the food although the food is fresh. She is just into fruits, she is not into other grins and rice and vegetables. When she eats fruits she doesn t complain about any foul smell but when she eats any of the grains(dal), bread, rice or vegetables she just can t eat them properly as she gets some kind of foul smell out of them. She is 22 years old, her weight is 55kgs, she is not a working woman she is homemaker. One more thing Doc, she don t exercise regularly what exercises do you suggest for her?