Hunger

Hunger is one of the basic needs of a Sim. Not fulfilling this need can result in death.

The Sims
For obvious reasons, a Sim cannot survive for very long without food. As long as you have a refrigerator, a Sim can have a snack, a quick meal (think TV dinner), or a regular meal, or can serve a group meal (which is the same as a regular meal except one Sim prepares several servings). If Unleashed is installed, Sims can grow or buy vegetables and store them in a pantry. They can then go to the pantry and prepare a regular or group meal without being charged for it. They can also get snacks from a pantry, even if it's empty.

If your Sim is lacking a refrigerator for whatever reason, or is unable to cook, he or she can also phone for a pizza. However, eating a pizza is not nearly as fulfilling as cooking a meal, and it can take quite a while for it to arrive. The higher a Sim's Cooking skill is, the better; this enables them to not only prepare food faster and more efficiently, the food they make also fills up the Hunger meter more. Also, they have less chance of causing a fire.

Of course, if a Sim's Hunger meter reaches zero, the Sim dies of starvation. Therefore, it is essential that it does not reach zero. Sims will inform you if they are hungry, usually by refusing to do tasks, or becoming extremely grumpy. A Sim who goes to work or school hungry will not do well.

There are different factors that go towards how satisfying a meal is, and therefore how much it fills up the Hunger meter. For example, a better fridge will yield a more satisfying meal, as will the type of cooking implement and the type of preparation surface - a food processor is best, followed by a bare counter, and finally, by the surface of the dishwasher.

The Sims 2
In Sims 2, a Sim may have a meal or serve a group meal. The type of food that can be prepared depends on the time of day and the Sim's Cooking skill. There is no "quick meal" option, but Sims can always have an instant meal-in-a-can. (Open for Business added the ability to Make any type of food the Sim is able to prepare at any time, but the Sim will not eat or serve that food unless you direct them to.)

How well a meal fills the Hunger meter primarily depends on the type of food. It can be affected by factors such as the quality of the stove or oven, the quality and cleanness of the preparation surface, and the use of a food processor. (If present, a food processor will automatically be used for foods that require chopping.) Some types of food may be more satisfying if the Sim preparing them has a higher level of Cooking skill than is needed to be able to make them.

Hunger in pets
Cats and dogs will look for their food bowls when they're hungry. In the Sims 1 expansion pack Unleashed, the bowls can only be filled when they're empty, but they never need to be cleaned, and the food never goes stale in the bowl. In the Pets expansion pack for Sims 2, you can clean a pet's bowl and refill it with fresh food, even if it's not empty. If your pets' bowls aren't clean and full of fresh food, they'll be forced to go rooting around in the trash. Small pets must also be fed by interacting with their cage.