Food

According to Wikipedia: Food is any substance, usually composed primarily of carbohydrates, fats, water and/or proteins, that can be eaten or drunk by an animal or human being for nutrition or pleasure.

For the Sims it's a lot easier. No food = low hunger = starvation = death.

Food is most often taken from a refrigerator.

The Sims
The Sims featured only a few types of food. Sims with a fridge can have a snack, or can prepare a meal. The meal will be either steak and beans, a salad, or a can of beans, depending on what else is available. If the Sim doesn't have, or can't get to, a stove, microwave, or toaster oven, the meal becomes a salad. If the Sim doesn't have, or can't get to, a preparation surface, the meal becomes a can of beans. Sims can choose to have a 'quick meal', which does not need to be prepared, but does need to be cooked. Sims can use the BBQ grill to cook a plate of hamburgers. Sims do not have to buy food, but are charged each time they prepare a meal or have a snack. They are charged §20 for a group meal (which serves six), §10 for a single meal, and §5 for a snack. (If Unleashed is installed, they are not charged for meals prepared from a pantry.) Sims can also use the phone to order pizza, which will cost them §40.

Later expansion packs provided more food for Sims to eat, including a birthday cake, cookies, and turkey. This food is bought from the Buy catalog, and is ready to eat when bought. Livin' Large added Servo, which will produce free food when told to serve a meal (but not very good food at all). But the most significant upgrade was that of Makin' Magic, which provided an baker's oven which allows Sims to cook more types of food, as long as the required ingredients were in the Sim's inventory.

The Sims 2
Food in The Sims 2 is more complicated, featuring many new choices, like Mac and Cheese, Lobster Thermidor and Baked Alaska. Food is even classified into three types: Snacks, Meals and Dessert, with meals also broken down depending on the time of day: Breakfast, Lunch and Dinner. (Open for Business added the ability to Make any type of food 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.)

The types of food Sims can prepare depends on their level in the Cooking skill. Also, some foods require certain equipment to make, ie., needing a microwave to make Cup O' Ramen (University)

One difference from Sims 1 is that it's possible for a Sim to become distracted while waiting for their food to cook, especially if they're using an oven. This can result in a burned meal, or even a fire. Even if the Sim doesn't get distracted, they can still burn a meal, as even the best cooks don't always get it right. Another difference is that cold foods, such as cereal and lunch meat sandwiches, are available, so Sims with little Cooking skill can eat without risking fire. Also, Sims 2 fridges occasionally have to be restocked, which means that it's necessary to buy groceries once in a while.

Children can only prepare food using the toy oven, which makes cupcake that are fairly filling.

Later expansion packs such as Holiday Party Pack, Open for Business and Seasons added more foods for Sims to cook. Bon Voyage adds special foods that can only be eaten on vacation.

Strangely, foods that are in the water still burn.

Modded Food
Modded food (Modified food) is food downloaded from sites like The Sims Resource and ModTheSims2. These sites have a dedicated "food" section, where you can download several types of food like ice cream, Chinese chicken and French bread. Earlier versions of food for The Sims 2 have had many problems which creators tried to overcome, like food not disappearing, among other things.

The Sims 3
Food in The Sims 3 can be moved out of the fridge by clicking on it and clicking "open". Some foods can also be downloaded from ModTheSims2. This mod makes recipes more complex, and if your Sim doesn't own any of the ingredients, he or she has to pay a high price. Unlike The Sims 2, food of your choice can be bought from a grocery store.