Nutrition Basics: Chapter 11 - Energy Balance and Body Weight

Vocabulary terms and definitions covering body mass index, energy balance, metabolic rates, eating disorders, and health recommendations from Nutrition Basics Chapter 11.

body mass index (BMI)

A measurement calculated using height and weight that is more predictive of body fatness than weight alone.

BMI Formula (Imperial)

$$BMI = [weight (lb) \times 703] \div height (in)^{2}$$

BMI Formula (Metric)

$$BMI = [weight (kg)] \div height (m)^{2}$$

Underweight (BMI Category)

A BMI of less than $18.5$.

Normal weight (BMI Category)

A BMI range of $18.5-24.9$.

Overweight (BMI Category)

A BMI range of $25-29.9$.

Obese (BMI Category)

A BMI of $30.0$ or greater.

Optimal body fat content (female)

Between $20$ and $30$ percent of total weight.

Optimal body fat content (male)

Between $12$ and $20$ percent of total weight.

Methods for measuring body fat content

Skin-fold test, underwater weighing, Bioelectric Impedance Analysis (BIA), and dual-energy X-ray absorptiometry.

visceral fat

Fat deposited in the abdominal cavity; a better predictor of disease risk than total fat mass.

waist circumference

Measurement around the natural waist (usually the narrowest point) used to measure abdominal obesity.

waist-to-hip ratio

Waist circumference divided by hip circumference; often considered a better predictor of disease risk than waist circumference alone.

Positive energy balance

State where excess nutrient energy is stored or used for growth, occurring during childhood, pregnancy, or wound healing.

Negative energy balance

State where energy intake is insufficient, requiring the body to use stored energy.

Estimated Energy Requirement (EER)

Energy intake estimation to preserve energy balance in healthy adults based on age, biological sex, weight, height, and physical activity.

METS (metabolic equivalents)

A measurement based on oxygen consumption; one MET equals $3.5\,ml/kg\,\text{body weight}/min$ in adults.

total energy expenditure (TEE)

The sum of energy used for basal metabolism, food digestion and absorption, and physical activity.

basal metabolism

Metabolic pathways necessary to support and maintain basic body functions, accounting for $50$ to $70$ percent of daily energy expended.

basal metabolic rate (BMR)

The amount of energy required by the body to conduct its basic functions over a certain time period.

hunger

An unpleasant sensation of feeling empty communicated to the brain by mechanical and chemical signals.

satiety

The sensation of feeling full, determined by mechanical and chemical signals.

leptin

A hormone produced by fat tissue that communicates to the satiety center in the hypothalamus that the body is in positive energy balance.

sedentary behavior

Activity where energy expenditure is no more than $1.5$ times the amount of energy expended while at rest (e.g., sitting or lying awake).

healthism

The idea that health is an individual's moral responsibility and that they must meet society's definition of healthy to be productive.

Health at Every Size (HAES) movement

A weight-inclusive, non-diet approach to healthcare that focuses on intuitive eating, physical/emotional health, and movement rather than weight loss.

Anorexia Nervosa

A psychiatric illness where a person obsesses about weight and food, resulting in extreme nutrient inadequacy and high mortality rates.

Bulimia

A psychiatric illness characterized by frequent episodes of eating large amounts of food followed by purging (e.g., vomiting or excessive exercise).

Binge Eating Disorder

A psychiatric disorder characterized by periodic losses of control over eating, often linked to guilt, shame, and depression.

Avoidant/restrictive food intake disorder (ARFID)

Formerly known as Selective Eating Disorder; characterized by restrictive eating without the body-image issues found in anorexia.

Other Specified Feeding or Eating Disorder (OSFED)

Disorders that cause distress but do not fit the specific criteria of other eating disorders.

orthorexia nervosa

An unhealthy obsession with the quality of food and eating healthy rather than food quantity or weight loss.

Clinically meaningful weight loss

A weight loss of $5-10$ percent of body weight, which is sufficient to reduce chronic disease risk.