You need food/drink for both. If you learn the cooking skills then you can make your own. Then again, if you find a Food Vendor, you can just buy food. I know there are some people in the game who do not cook at all.
If you work on Animal Kinship, large stacks of meat will make you rather full. If you work on Gardening and harvesting skills, large stacks of eggs should do the trick. If you can cook of course, you can make your own food. Otherwise, you'll need to buy food from the food vendor or auctions.
Drinks can be purchased from Helga the drinks vendor in West Spice, or from auctions. They become less necessary as your skills increase, since they start to grant mood bonuses from everyday actions.