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Lifestyle and Hunger

A modern, stressful lifestyle may increase clients' appetites, putting them at risk for weight gain and disease.

Hunger is a healthy signal that prompts us to search for food and to eat. Since eating is essential for survival, Mother Nature has set us up with a good strong urge to consume tasty food. Unfortunately, the physiological systems that may have worked well in the past can complicate people's efforts to avoid overeating today.

Hunger and satiety

The term hunger refers to the biological drive to eat. Hunger's opposite, a feeling of having had enough to eat, is called satiety. Many different hormones and physiological systems influence feelings of hunger and satiety. For example, the hormone ghrelin is released by the stomach, and, as ghrelin levels rise, hunger increases. As a person eats, these levels fall as the stomach senses the presence of food. Similarly, as food reaches the small intestine, it releases several neurochemicals, including cholecystokinin, which promote many digestive processes and tell the brain that the body is no longer ravenous.

Another important chemical messenger is the hormone leptin. Leptin is manufactured by fat cells and helps to inform the body (including the brain) about total fat stores. It helps to regulate other physiological functions as well, including reproduction and glucose metabolism. In general, higher leptin levels are associated with less hunger, although this relationship appears to be disrupted in people who are obese.


Appetite refers to a person's desire to eat. Appetite is affected by hunger, of course, but also includes other physical and psychological drives. Appetite can prompt someone to eat even in the absence of hunger. Who hasn't had the experience of finishing a large meal, feeling full or even stuffed, and still felt the desire for the delicious dessert being served?

A "healthy appetite" encourages someone to eat an assortment of foods with a variety of colors, flavors and textures. This helps them consume adequate amounts of the more than 40 nutrients they need to stay healthy. Appetite makes eating pleasurable, and lets people enjoy their food.

Lifestyle and the drive to eat

While strong hunger and appetite signals encourage survival in a climate of scarcity, they cause people to overeat in the land of plenty. Tastes for fat, salt and sugar lead people to eat too many processed, high-calorie foods. A poor diet not only causes obesity, but also interferes with the regulation of glucose and fats in the body, contributing to artery disease, diabetes, hypertension and some types of cancer.

But it gets worse. A modern lifestyle not only presents people with a smorgasbord of delicious food, it also interferes with their equilibrium by allowing them (encouraging them?) to become sedentary, sleep deprived and stressed. All of these can increase hunger and appetite, distract people from knowing when they are full, interfere with good food choices, and increase risk for obesity and chronic health problems.

Fitness professionals can help clients by teaching them about the interaction among lifestyle, hunger, appetite and satiety. You can help clients learn to tune in to their feelings of hunger and satiety, and work with their bodies to feel nourished and satisfied from their meals and snacks. Educate them about the importance of a healthful lifestyle that includes enough sleep and a balanced diet composed primarily of whole foods, including several servings of fruits and vegetables each day. Encourage clients to get plenty of physical activity, which helps normalize appetite and hunger, reduces feelings of stress, improves sleep quality and, of course, expends calories and promotes good health.

Ball, S.D., K.R. Keller, L.J. Moyer-Mileur, et al. Prolongation of satiety after low versus moderately high glycemic index meals in obese adolescents. Pediatrics 111(3): 488-494, 2003.
Chaput, J.P., and A. Tremblay. Acute effects of knowledge-based work on feeding behavior and energy intake. Physiology & Behavior 90(1): 66-72, 2007.
Elder, S.J., and S.B. Roberts. The effects of exercise on food intake and body fatness: A summary of published studies. Nutrition Reviews 65(1): 1-19, 2007.
Knutson, K.L., K. Spiegel, P. Penev and E. Van Cauter. The metabolic consequences of sleep deprivation. Sleep Medicine Reviews 11: 163-178, 2007.
Roberts, C.J. The effects of stress on food choice, mood and bodyweight in healthy women. Nutrition Bulletin 33(1): 33-40, 2008.
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