- 1: any of the instinctive desires necessary to keep up organic life; especially : the desire to eat
- 2a : an inherent craving <an insatiable appetite for work
Appetite is a term implying a strong desire to acquire or participate in, exemplified by terms such as sexual appetite or appetite for life. In the context of food, appetite is used to describe a wanting or liking for particular foods, usually on the basis of their sensory properties (taste and texture) or a psychological attribute (perceived value or symbolic status). In this way appetite is usually distinguished from hunger, which implies a desire or seeking for food arising from a state of need or nutritional deficit. At the beginning of the twenty-first century the understanding of appetite achieves special importance because of its potential role in the worldwide epidemic of obesity, sometimes called a pandemic. Given that, in many parts of the world, people are surrounded by a plentiful supply of food that prevents chronic hunger (though permitting normal meal-to-meal hunger), the capacity to eat food in the absence of hunger or in a low state of hunger assumes special importance. Consequently, understanding appetite and how it can be controlled are urgent tasks in the fight against the obesity epidemic.
Appetite can therefore be defined as a liking for particular foods, or an attraction for foods based on their perceived pleasantness. This is normally referred to as the hedonic dimension of food selection. This characteristic can be described as the subjective pleasure that is derived from the consumption of food; in turn, this can be measured by asking people to rate the magnitude or intensity of pleasure associated with eating or tasting foods. This pleasure arises from the interaction between the person's perceptual capacity (acuity of taste, smell, and sensory feedback from the mouth) and the physical properties of foods. The intensity of the pleasure therefore depends in part on internal (personal) and external (food-related) factors. These food factors can be natural, such as the presence of sweet carbohydrates in fruits or, and much more common now, the deliberate construction of powerful properties in the manufacturing process. It can be hypothesized that the industrial production of foods (designed to possess a combination of properties, for example, sweetness, fattiness, flakiness) has saturated the food supply in many parts of the world with an abundance of appetite-stimulating products. These products include chocolates and desserts, cheese, meat, and pastry combinations, and many types of fried snacks. The inherent attractiveness of such products can stimulate eating in the absence of any obvious need for nutrients.
Is there a biological basis for appetite and for the degree of attractiveness of specific types of foods? It does seem that human beings derive pleasure from particular food properties—the qualities of sweetness and fattiness are prominent. It is generally understood that, during the course of human evolution, a preference for foods with these properties would lead people to consume foods that possessed energy—yielding value, for example, the nutritional value of carbohydrates and the energy value of fats. Consequently the value of these traits for survival has almost certainly persisted until the present day, at which stage these genetic dispositions may be detrimental in the current "obesigenic" environment (but useful when foods with these properties were scarce). The word "obesigenic" was coined around the end of the twentieth century to suggest an environment that promoted weight gain through the abundance, attractiveness, and marketing of food consumption, together with reduced opportunities for physical activity. It is recognized that most cultures contain highly prized food habits based on foods that are either sweet or fatty, and sometimes a combination of both—when the palatability can be intense.