feeding 10 week old puppy

Question
Our vet told us that our puppy was extremely overweight when we got her a few weeks ago.  She's a bichon. She's  now 9 weeks and is five pounds. We feed her 1/8 c. of food three times a day. She shakes and gets so excited when she eats, acting as though she is starving. She doesn't chew her food either. We tried giving her food that has bigger chunks, but she doesn't chew that. She does try to eat the grass and chews that though.  Should we feed her more? Should she really be on a 'strict' diet when she's growing?  Isn't it unhealthy for her not to chew her food? I've tried to feed her piece by piece but she won't chew it. Thanks in advance for your help.

Answer
Overweight and so young? its not possible chances are she had a fat tummy because she had worms...alot of puppy from bad breders will have very full or fat tummies that are full of worms. I reccomend feeding what she wants at each meal three times daily start feeding what the kibble package reccomends when she is 5 months old.