1. Fairy dust: from Ophilia the fairy, at the park water fountain. Buy the gold doubloon when it shows up and throw it into the water fountain at the park. Then you need to feed her fruit (from All Foods): strawberry, then kiwi, then apple, then mango, then cantaloupe, then watermelon. Next time you visit her she'll give you the dust. (Be sure to visit her one more time to take her home, you'll need her later).
2. Fresh Greens: From Diane at All Foods. Keep bringing her food made with fruit until she tells you that she's not gaining weight fast enough. Then go to Tiffany at the Lab and buy the weight gain aid from her (or add to your lab debt). Next time you visit her she'll give you the greens.
3. Perfect Bagel: from the baker at Sweet Cravings. Keep picking the option to share donuts with the baker until she reaches the point she says she's on a diet, then give her the BE vial from Shadowed Curios. Next time you visit her she should give you the bagel (if she doesn't give it to you right away, visit at a higher weight stage).
4. Wagyu (high quality) beef: from the waitress at the all-you-can eat cafe. Keep going there and tipping her until there's an option to give her the AE vial from Shadowed Curios. Next time you visit there should give you the meat.
5. Condiments: From Sandra at the park hot dog stand. Keep competing and beating her at the hot dog eating contest and eventually she should give you these.
6. Flavor Enhancer: From the Cici quest, however you choose to end it. Keep feeding her, either meat or people depending on what route you chose. When Cici reaches immobility will be an option to "pass", do that, go see Tiffany. If you side with Cici, go visit her one more time and you'll get the flavor enhancer from her. If you side with Tiffany, go to the lab and she'll give it to you.