Jewish Dietary Laws

Making everyday eating part of religious life

Jewish dietary laws are called kashrut. They govern which foods may be eaten, how meat is prepared and which foods must be kept apart. Kosher means fit or acceptable according to Jewish law; trefah, also called treif, means food that is not permitted. These are religious categories, not judgements about whether food is hygienic.

Kashrut makes an ordinary activity—buying, preparing and eating food—an opportunity to practise faith. For Jews who observe it, deciding what to eat can express obedience to God, develop self-control and reinforce Jewish identity. However, Jews differ over how closely these laws should be followed and why they matter.

Which foods are permitted?

The Written Torah sets out dietary laws, particularly in Leviticus and Deuteronomy. Leviticus 11:3 permits an animal that has a split hoof and chews the cud. Chewing the cud means bringing partly digested food back into the mouth and chewing it again.

A mammal must meet both conditions. Cattle and sheep do, so their meat can be kosher if it is prepared correctly. Pigs have split hooves but do not chew the cud, so pork is trefah. Permission to eat a species is only the first stage: beef is not automatically kosher simply because it comes from a cow.

Fish must have both fins and scales. Shellfish, such as prawns and crabs, do not meet these conditions and are trefah. The Torah also prohibits various birds, including birds of prey; domestic poultry such as chicken is permitted when prepared correctly. Almost all insects are forbidden, with an exception for certain types of locust.

Fruit and vegetables are permitted, but they must be checked and cleaned to remove insects. Milk and eggs must come from permitted animals and birds. Processed foods also require attention because their ingredients or preparation may make them unsuitable.

Why the preparation of meat matters

Permitted mammals and birds must undergo shechitah, the prescribed Jewish method of slaughter. It is performed by a trained and qualified shochet, using a very sharp knife. The method is intended to minimise suffering, reflecting the Jewish prohibition on causing unnecessary pain to animals. Fish do not require shechitah.

Blood must also be removed from meat. Deuteronomy 12:23 teaches that “the blood is the life” and prohibits consuming it. Meat is drained and treated to remove blood before it is eaten. Animals that have died naturally or been killed by other animals are not permitted food.

These requirements show that kashrut concerns more than a list of animals: the way food reaches the table matters too.

Keeping milk and meat separate

Exodus 23:19 commands: “Do not boil a kid in its mother’s milk.” Here, a kid means a young goat. Rabbinic interpretation develops this teaching into rules against cooking or eating meat and dairy together.

A cheeseburger therefore combines foods that observant Jews keep apart: meat and cheese made from milk. Either ingredient might be permitted separately, but their combination is not. Many observant Jews also wait after eating meat before consuming dairy; the waiting period varies between traditions and can be up to six hours.

Separation affects the kitchen as well as the meal. Observant households use separate utensils, crockery and cooking equipment for meat and dairy. Some also have separate preparation areas or storage arrangements. This prevents the foods from being mixed during preparation or serving.

Foods containing neither meat nor dairy are called parev. Examples include fruit, vegetables, rice and eggs from permitted birds. Parev foods can accompany either meat or dairy, provided their ingredients and preparation meet kosher requirements. Vegetarian food may contain dairy, so it is not necessarily parev.

Different Jewish approaches to observance

Orthodox Judaism regards the dietary commandments and their traditional interpretation as binding. An Orthodox Jew who observes kashrut therefore follows the rules even when doing so is inconvenient. Their authority comes from God and Jewish law, rather than depending only on whether an individual finds a rule useful.

Reform and Liberal Jews place greater emphasis on informed personal choice. Some observe all the traditional rules, others keep selected rules, and some keep kosher at home but are less strict elsewhere. This does not necessarily mean that food has no religious significance for them: they may understand that significance differently.

One Reform approach emphasises the ethical purpose of eating habits. Rabbi Benji Stanley argues that kashrut can cultivate reverence for life through repeated everyday choices. This might encourage someone to limit meat consumption or adopt a vegetarian or vegan diet. Others place greater importance on moral conduct than on detailed ritual restrictions. These are differing approaches within Judaism, not a single view shared by every Reform or Liberal Jew.

How important are dietary laws?

The case for their importance is that kashrut turns belief into daily action. Observing it expresses obedience to God and connects individuals with Jewish tradition. Shared food practices can strengthen family and community identity. In Great Britain, kosher shops, restaurants and supermarket sections help observant Jews maintain these practices.

The restrictions also influence social life. Eating at a friend's house or choosing a restaurant may require checking ingredients and preparation. Some Jews avoid non-kosher restaurants altogether. This can demand planning, but an observant Jew may regard that commitment as part of the value of keeping the commandments.

A contrasting argument is that religious commitment should be judged primarily through ethical behaviour, rather than exact observance of food rules. Someone taking this approach might prioritise animal welfare or responsible consumption. Yet the two positions need not be opposites: dietary rituals can themselves encourage ethical reflection and self-discipline.

A justified conclusion therefore depends on how a Jew understands religious authority and the purpose of the laws. Traditional observance can be central to obedience and identity, while other Jews express their commitment through selective observance or ethical food choices.