Eating behavior is a complex interplay between hunger, appetite and satiety. Understanding the factors that affect eating behavior is important for understanding what we eat and why. Need to Eat vs. Want to Eat Hunger is the physiological need for food.
Numerous physiological cues tell us we are hungry, such as an empty or growling stomach, a decrease in blood glucose levels, and alterations in circulating hormones (e.g., increased glucagon and ghrelin and decreased insulin). Appetite is the psychological desire to eat, and is associated with sensory experiences or aspects of food such as the sight and smell of food, emotional cues, social situations, and cultural conventions. Hunger acts as the more basic drive, while appetite is more of a reflection of eating experiences. At times we are not hungry but have an appetite (such as seeing a tempting desert after eating full meal) or may be hungry but have not appetite (such as when we are sick). Both hunger and appetite determine what, when, and why we eat
Satiety
A “gut check” on fullness The other side of hunger and appetite is satiety, which is the physiological and psychological experience of “fullness” that comes after eating and/or drinking. As was true for hunger and appetite, a number of factors influence the experience of satiety including gastric distention, elevations in blood glucose and alterations in circulating hormones (e.g., increased insulin and cholecystokinin, and decreased glucagon). Fostering a Full Feeling Generally speaking, feeling full is a function of the amount of food one eats; that is, it typically takes a whole sandwich, not just a bite, to promote satiety.
Fullness can inhibit further eating too soon or too late. Early satiety may cause malnutrition and unintentional weight loss. Whereas, late fullness can cause weight gain and its associative health consequences. Therefore, knowing what causes