Metabolism: Energy Balance Flashcards

Flashcards covering key metabolic concepts, energy balance, components of energy expenditure, adipose tissue types, genetic influences on weight, and nutritional genomics from the lecture notes.

Metabolism

The sum of all chemical changes that occur in cells, tissues, or the body.

Balanced Energy State

When 'calories in' equals 'calories out', leading to a stable body weight.

Positive Energy Balance

When 'calories in' are greater than 'calories out', leading to weight gain.

Negative Energy Balance

When 'calories in' are less than 'calories out', leading to weight loss.

Anabolism

The metabolic process of synthesizing new proteins, lipids, and nucleic acids (DNA).

Catabolism

The metabolic process of breaking down molecules to capture their chemical energy as ATP.

Total Energy Expenditure (TEE)

The total number of calories burned by the body in a day, composed of Basal Metabolic Rate (BMR), the Thermic Effect of Food, and Activity.

Basal Metabolic Rate (BMR)

The number of calories a person would burn even if they slept all day and night, measured at rest in a thermo-neutral, post-absorptive state.

Resting Metabolic Rate (RMR)

The energy used by the body after eating and resting, less restricted than BMR, and typically about 10% higher than BMR.

Sarcopenia

The age-related loss of muscle mass, which can lead to a decrease in Basal Metabolic Rate (BMR).

Thermic Effect of Food (TEF)

The energy expenditure associated with the digestion, absorption, and storage of food, typically accounting for about 10% of total calorie intake.

Non-exercise Activity Thermogenesis (NEAT)

All the energy expended for everything we do that is not sleeping, eating or sports-like exercise; it can range from 15% to over 50% of total daily energy expenditure.

White Adipose Tissue (WAT)

Stores fat in a single large droplet per cell, primarily for energy storage.

Brown Adipose Tissue (BAT)

Stores fat in multiple small droplets per cell and is rich in mitochondria, specializing in heat production through non-shivering thermogenesis.

Non-shivering Thermogenesis

Heat production in the body without muscle contraction, primarily facilitated by brown adipose tissue through uncoupling proteins.

Metabolic Inefficiency

A metabolic state where catabolism is uncoupled from ATP production, leading to energy being released as heat rather than being stored, often involving uncoupling proteins.

Nutritional Genomics

The study of how people's food choices can affect their gene expression and how inherited genetic variations influence the body's responses to nutrients.

Nutrigenetics

The study of how inherited genetic variations influence the body’s responses to specific nutrients and nutrient combinations.

Nutrigenomics

The study of how nutrients affect the expression of a person's genome.

Body Mass Index (BMI)

A measure calculated as weight (Kg) divided by the square of height (meters^2), used to categorize body weight into categories like underweight, healthy, overweight, and obese.

Respiratory Exchange Ratio (RER)

The ratio of the volume of carbon dioxide released (VCO2) to the volume of oxygen absorbed (VO2), used to estimate the Respiratory Quotient (RQ).

Respiratory Quotient (RQ)

An indicator reflecting which fuel source (carbohydrate, lipid, or protein) is primarily being metabolized, calculated as the ratio of CO2 produced to O2 consumed at cellular level.