Humans are omnivores: their diet includes grains, vegetables, fruit, legumes, nuts, meat, fish, eggs and dairy products. Most food is cooked, and diet varies greatly by region and culture; an adult needs about 2,000–2,500 kcal and roughly 1.5–2 litres of water a day. Many religions restrict food. In Islam (halal), beef, mutton, goat, camel, chicken and most fish are permitted when slaughtered ritually, while pork, carrion, blood, predatory animals and alcohol are forbidden. In Judaism (kashrut), meat of ruminants with split hooves — cattle, sheep, goats, deer — certain birds such as chicken, duck, goose and turkey, and fish with fins and scales are permitted, while pork, rabbit, shellfish and mixing meat with milk are forbidden. Hindus do not eat beef and many are vegetarian, Jains follow strict vegetarianism, and many Buddhists avoid meat. There are also fasts: Ramadan in Islam, Yom Kippur and other fasts in Judaism, and Lent among Orthodox, Catholic and other Christians. Regardless of religion, doctors do not recommend alcohol: it is toxic and carcinogenic, and according to the WHO there is no safe dose. Excess salt, sugar and trans fats, processed meat and large amounts of red meat are also harmful. Raw or undercooked meat and eggs, raw milk, spoiled food and poisonous mushrooms and plants are dangerous.