Hunger

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

Cooking
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 an instant meal-in-a-can, a regular meal, or can serve a group meal (which is the same as a regular meal except one Sim prepares several servings).

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. Also, a pizza is more expensive as a group meal, costing §30-40 instead of §20. A teen or adult Sim without a refrigerator can also satisfy hunger by cooking food on a barbecue.

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,

Starvation
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 the player if they are hungry, usually by refusing to do tasks, or becoming extremely grumpy. In The Sims 3, they will receive a hungry moodlet. A Sim who goes to work or school hungry will not do well. Babies, toddlers, and children will be taken away by the social worker before they can starve to death.

Hunger moodlets
Neglecting the hunger need will give a hungry Sim the "hungry" moodlet for three 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 have their hunger motive replaced with thirst. This motive is filled by drinking Plasma, the Sim-equivalent of blood. They can get plasma by draining Sims, from Plasma Fruit, which is a new plant, or by snacking on Plasmapacks. Similar to death by starvation, Vampires can die by thirst, but unlike the usual purple ghost, the ghost is red, with a pulsing red light beating where the heart would be. The image on the tombstone is that of a bat.