223
utritional status describes the condition of the body
related to the availability and use of nutrients.
Nutrients that are taken into the body can be used to
provide the energy needed to perform various body func-
tions or they can be stored for future use. The stability of
body weight and composition of lean-to-fat tissue ratio
over time requires that a person’s energy intake is bal-
anced with energy expenditure. Also, because different
foods contain different amounts of proteins, fats, carbo-
hydrates, vitamins, and minerals, appropriate amounts
of these nutrients must be maintained to ensure that the
body’s metabolic systems are adequately supplied. This
chapter discusses nutritional status, overnutrition and
obesity, and undernutrition and eating disorders.
Energetics and Nutritional
Status
The nutrients from the foods we eat are used by cells
to provide the body with the energy needed to perform
almost all cellular functions. Energy is measured in heat
units called
calories
. A calorie, spelled with a small “c”
and also called a
gram calorie
, is the amount of heat or
energy required to raise the temperature of 1 g of water
by 1°C. A
kilocalorie
(kcal), or
large calorie
(abbrevi-
ated as a capital C), is the amount of energy needed to
raise the temperature of 1 kg of water by 1°C. Because
a calorie is so small, kilocalories often are used in nutri-
tional and physiologic studies.
Energy Metabolism
Metabolism
is the organized process through which
nutrients—carbohydrates, fats, and proteins—are bro-
ken down, transformed, or otherwise converted into
cellular energy. The oxidation of carbohydrates and
proteins provides 4 kcal/g, whereas fats yield 9 kcal/g.
1
The process of metabolism is unique in that it enables
the continual release of energy, and it couples this energy
with physiologic functioning. For example, the energy
N
Disorders of
Nutritional
Status
10
C h a p t e r
Energetics and Nutritional Status
Energy Metabolism
Nutritional Status
Dietary Reference Intakes
Calories
Proteins, Fats, and Carbohydrates
Vitamins and Minerals
Fiber
Regulation of Food Intake
Hunger, Appetite, and Satiety
Regulatory Mechanisms
Assessment of Energy Stores and Nutritional
Status
Anthropometric Measurements
Laboratory Studies
Overweight and Obesity
Causes of Overweight and Obesity
Adipose Tissue
Adipose Tissue as an Endocrine Organ
Adipose Tissue and the Inflammatory Process
Types of Obesity
Prevention and Treatment of Obesity
Childhood Obesity
Undernutrition and Eating Disorders
Malnutrition and Starvation
Protein-Energy Malnutrition
Malnutrition in Trauma and Illness
Diagnosis
Treatment
Eating Disorders
Anorexia Nervosa
Bulimia Nervosa
Binge-Eating Disorder
