Metabolism, Energy Balance, Body Composition & Obesity Practice Flashcards

A set of practice flashcards covering vocabulary and core concepts related to energy balance, metabolism, and body composition based on lecture notes.

Energy Metabolism

The network of chemical reactions that build compounds, contract muscles, conduct nerve impulses, pump ions across membranes, and sustain life.

$ATP$ (Adenosine Triphosphate)

The body's usable energy source, consisting of adenosine and three phosphate groups, which releases energy when phosphate bonds are broken.

Energy Equilibrium

A state where energy intake equals energy expenditure, resulting in a stable body weight.

Negative Energy Balance

A state where energy output exceeds energy intake, leading to weight loss and the breakdown of stored fat, muscle, and potentially lean tissue.

Positive Energy Balance

A state where energy intake exceeds energy output, resulting in weight gain; it is necessary during pregnancy, childhood, adolescence, and recovery from illness or injury.

Bomb Calorimeter

An instrument used to measure the energy content of food by burning it in a sealed chamber and measuring the temperature increase in the surrounding water.

Basal Metabolism ($BMR$)

The largest component of energy expenditure (about $60-70\%$), representing the energy needed for life-sustaining functions such as heart beating and breathing at rest, excluding digestion.

Physical Activity

The second largest source of energy expenditure ($25-40\%$), which depends on body weight, muscle mass, intensity, duration, and frequency of movement.

Thermic Effect of Food ($TEF$)

The energy required to digest, absorb, transport, metabolize, and store nutrients, accounting for approximately $5-10\%$ of total energy expenditure.

Thermogenesis

A minor energy expenditure component (less than $1\%$) involving heat production from activities like shivering, fidgeting, and maintaining posture.

Direct Calorimetry

A method of measuring energy expenditure by tracking the amount of heat released by the body.

Indirect Calorimetry

The most common method of measuring energy expenditure, based on the predictable relationship between oxygen consumed and carbon dioxide produced.

Estimated Energy Requirement ($EER$)

A formula-based estimation of energy needs using height, weight, age, sex, and physical activity, though it is considered the least accurate due to individual variations.

Hunger

The physiological drive to eat, controlled by internal signals, hormones, and the nervous system.

Appetite

The psychological desire to eat, influenced by external factors like emotions, smells, advertising, and social settings.

Satiety

The feeling of fullness after eating that helps stop food intake, regulated by stomach stretching, hormones, and nutrient absorption.

Body Mass Index ($BMI$)

A weight-for-height assessment tool calculated using the formula $\text{BMI} = \frac{Weight\,(kg)}{Height^2\,(m^2)}$.

Healthy Weight $BMI$

A $BMI$ range between $18.5$ and $24.9$.

Overweight $BMI$

A $BMI$ range between $25.0$ and $29.9$.

Obese $BMI$

A $BMI$ value of $\geq 30$.

High-Risk Waist Circumference

A measurement of fat distribution indicating increased health risk, defined as greater than $40\,\text{inches}$ for men and $35\,\text{inches}$ for women.

Obesity

Excessive body fat relative to lean body mass that presents a health risk.

Hypertrophic Obesity

A form of obesity where the size of existing fat cells increases, most common in adults.

Hyperplastic Obesity

A form of obesity characterized by an increase in the total number of fat cells, often developing during childhood.