Phylogenetic analysis suggests that human ancestors may have invented cooking as far back as 1.8 million to 2.3 million years ago. Re-analysis of burnt bone fragments and plant ashes from the Wonderwerk Cave, South Africa, has provided evidence supporting control of fire by early humans there by 1 million years ago. There is evidence that Homo erectus was cooking their food as early as 500,000 years ago. Evidence for the controlled use of fire by Homo erectus beginning some 400,000 years ago has wide scholarly support. Archaeological evidence from 300,000 years ago, in the form of ancient hearths, earth ovens, burnt animal bones, and flint, are found across Europe and the Middle East. Anthropologists think that widespread cooking fires began about 250,000 years ago, when hearths started appearing.
Some people have allergies or sensitivities to foods which are not problematic to most people. This occurs when a person's immune system mistakes a certain food protein for a harmful foreign agent and attacks it. About 2% of adults and 8% of children have a food allergy. The amount of the food substance required to provoke a reaction in a particularly susceptible individual can be quite small. In some instances, traces of food in the air, too minute to be perceived through smell, have been known to provoke lethal reactions in extremely sensitive individuals. Common food allergens are gluten, corn, shellfish (mollusks), peanuts, and soy. Allergens frequently produce symptoms such as diarrhea, rashes, bloating, vomiting, and regurgitation. The digestive complaints usually develop within half an hour of ingesting the allergen.
German research in 2003 showed significant benefits in reducing breast cancer risk when large amounts of raw vegetable matter are included in the diet. The authors attribute some of this effect to heat-labile phytonutrients. Sulforaphane, a glucosinolate breakdown product, which may be found in vegetables such as broccoli, has been shown to be protective against prostate cancer, however, much of it is destroyed when the vegetable is boiled.
The Mayo Clinic Diet is the official diet developed by Mayo Clinic, based on research and clinical experience. It focuses on eating healthy foods that taste great and increasing physical activity. It emphasizes that the best way to keep weight off for good is to change your lifestyle and adopt new health habits. This diet can be tailored to your own individual needs and health history — it isn't a one-size-fits-all approach.
Some foods not from animal or plant sources include various edible fungi, especially mushrooms. Fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina. Inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient.