You get a pill from one your friends in office which will help lily gain weight. Visit your frnd after office.
You can refer to my old comments in this thread to unlock all the ingredients.
Complete the following people's quest:
1. Win all the hotdog contests to get homemade condiments.
2. Complete cici's quest of feeding her different people to get flavour enhancers.
3. Help diana gain weight to get fresh greens.
4. Give the AE/BE/Hyper serum to bakery, buffet and the black coat lady at your office respectively. The bakery girl will give you bread and the buffet girl meat.
5. Unlock the fairy, feed her and she will give you fairy dust.