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 a refrigerator is available, 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 a 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 The 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 (except for a TV dinner) the Sim is able to prepare at any time, but the Sim usually won't 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.

As in The Sims, Sims will die of starvation if their Hunger meter reaches zero. However, babies, toddlers, and children will be taken away by the Social Worker before they can starve to death.

The Sims 3
Neglecting the hunger need will give a hungry Sim the "hungry" moodlet for two hours. After that, it will be replaced with "very hungry", which will last for one day. If the Sim still hasn't eaten by the time that moodlet expires, he or she will finally get the "starving" moodlet. If that moodlet expires, the hungry Sim will die of starvation. Toddlers have the second two moodlets for 12 hours and babies have "Very Hungry" and "Starving" for a mere 8 hours.

Sims can also buy the "Hardly Hungry" lifetime reward for 25,000 lifetime points. This will cut the decay rate of hunger to ¼ of usual.

Thirst
Vampires in The Sims 3: Late Night will have their hunger motive replaced with thirst. This motive is filled by drinking Plasma, the sim-equivelant of blood. You can get plasma from draining Sims, Plasma Fruit from a new plant or snacking on Plasmapacks. Similar to death by starvation, Vampires can die by thirst.