Hunger (physiology) in the context of "Leptin"

Human food is food which is fit for human consumption, and which humans willingly eat. Food is a basic necessity of life, and humans typically seek food out as an instinctual response to hunger; however, not all things that are edible constitute as human food.

Humans eat various substances for energy, enjoyment and nutritional support. These are usually of plant, animal, or fungal origin, and contain essential nutrients, such as carbohydrates, fats, proteins, vitamins, and minerals. Humans are highly adaptable omnivores, and have adapted to obtain food in many different ecosystems. Historically, humans secured food through two main methods: hunting and gathering and agriculture. As agricultural technologies improved, humans settled into agriculture lifestyles with diets shaped by the agriculture opportunities in their region of the world. Geographic and cultural differences have led to the creation of numerous cuisines and culinary arts, including a wide array of ingredients, herbs, spices, techniques, and dishes. As cultures have mixed through forces like international trade and globalization, ingredients have become more widely available beyond their geographic and cultural origins, creating a cosmopolitan exchange of different food traditions and practices.

The insular cortex (also insula and insular lobe) is a portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes) within each hemisphere of the mammalian brain.

The insulae are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion, interoception, or the regulation of the body's homeostasis. These functions include compassion, empathy, taste, perception, motor control, self-awareness, cognitive functioning, interpersonal relationships, and awareness of homeostatic emotions such as hunger, pain and fatigue. In relation to these, it is involved in psychopathology.

The hypothalamus (pl.: hypothalami; from Ancient Greek ὑπό (hupó) 'under' and θάλαμος (thálamos) 'chamber') is a small part of the vertebrate brain that contains a number of nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. It forms the basal part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is about the size of an almond.

The hypothalamus has the function of regulating certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls body temperature, hunger, important aspects of parenting and maternal attachment behaviours, thirst, fatigue, sleep, circadian rhythms, and is important in certain social behaviors, such as sexual and aggressive behaviors.

Appetite is the desire to eat food items, usually due to hunger. Appealing foods can stimulate appetite even when hunger is absent, although appetite can be greatly reduced by satiety. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Appetite has a relationship with every individual's behavior. Appetitive behaviour also known as approach behaviour, and consummatory behaviour, are the only processes that involve energy intake, whereas all other behaviours affect the release of energy. When stressed, appetite levels may increase and result in an increase of food intake. Decreased desire to eat is termed anorexia, while polyphagia (or "hyperphagia") is increased eating. Dysregulation of appetite contributes to ARFID, anorexia nervosa, bulimia nervosa, cachexia, overeating, and binge eating disorder.

Polyphagia, or hyperphagia, is an abnormally strong, incessant sensation of hunger or desire to eat often leading to overeating. In contrast to an increase in appetite following exercise, polyphagia does not subside after eating and often leads to rapid intake of excessive quantities of food. Polyphagia is not a disorder by itself; rather, it is a symptom indicating an underlying medical condition. It is frequently a result of abnormal blood glucose levels (both hyperglycemia and hypoglycemia), and, along with polydipsia and polyuria, it is one of the "3 Ps" commonly associated with uncontrolled diabetes mellitus.

Satiety (/səˈtaɪəti/ sə-TY-ə-tee) is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of hunger. Following satiation (meal termination), satiety is a feeling of fullness lasting until the next meal. When food is present in the GI tract after a meal, satiety signals overrule hunger signals, but satiety slowly fades as hunger increases.

The satiety center in animals is located in ventromedial nucleus of the hypothalamus.