RETRIEVAL PRACTICE Take a moment to answer each of these Learning Objective Questions (repeated here from within this section). Then click the 'show answer' button to check your answers. Research suggests that trying to answer these questions on your own will improve your long-term retention (McDaniel et al., 2009).

Hunger pangs correspond to stomach contractions, but hunger also has other causes. Neural areas in the brain, some within the hypothalamus, monitor blood chemistry (including level of glucose) and incoming information about the body’s state. Appetite hormones include ghrelin (secreted by an empty stomach); insulin (controls blood glucose); leptin (secreted by fat cells); orexin (secreted by the hypothalamus); and PYY (secreted by the digestive tract). Basal metabolic rate is the body’s resting rate of energy expenditure. The body may have a set point (a biologically fixed tendency to maintain an optimum weight) or a looser settling point (also influenced by the environment).

Hunger also reflects our memory of when we last ate and our expectation of when we should eat again. Humans as a species prefer certain tastes (such as sweet and salty), but our individual preferences are also influenced by conditioning, culture, and situation. Some taste preferences, such as the avoidance of new foods, or of foods that have made us ill, have survival value.

Genes and environment interact to produce obesity. Obesity correlates with depression, especially among women. Twin and adoption studies indicate that body weight is also genetically influenced. Environmental influences include lack of exercise, an abundance of high-calorie food, and social influence.
     Those wishing to lose weight are advised to make a lifelong change in habits: Get enough sleep; boost energy expenditure through exercise; limit variety and minimize exposure to tempting food cues; eat healthy foods and reduce portion sizes; space meals throughout the day; beware of the binge; monitor eating during social events; forgive the occasional lapse; and connect to a support group.