Energy Expenditure and Metabolic Health Lecture Review

A complete set of flashcards covering energy expenditure, metabolic rates, hunger hormones, BMI categories, and medical weight-loss interventions based on lecture notes.

What are the three major components of energy expenditure?

BMR (Basal Metabolic Rate), TEF (Thermic Effect of Food), and TEE (Thermic Effect of Exercise).

What is the definition of Basal Metabolic Rate ($BMR$)?

The amount of energy the body uses to stay alive while at rest, fasting, and in a neutral-temperature environment.

Which component of energy expenditure is typically the largest contributor to daily calorie use?

Basal Metabolic Rate ($BMR$), accounting for more than half of total daily energy expenditure.

What functions are supported by $BMR$?

Breathing, heartbeat, brain function, circulation, maintaining body temperature, organ function, waste excretion, and immune surveillance.

What is the definition of the Thermic Effect of Food ($TEF$)?

The energy the body uses to digest, absorb, transport, and store nutrients from food.

Approximately what percentage of daily energy expenditure is attributed to $TEF$?

About $10\%$.

What is the Thermic Effect of Exercise ($TEE$)?

The energy the body uses during physical activity, which varies the most from person to person.

What factor most strongly determines a person's $BMR$?

Lean muscle mass.

Why do males generally have a higher $BMR$ than females of the same size?

Males usually have more lean muscle mass.

At what age does muscle mass typically begin to decline, and at what rate?

Around age $25$, at a rate of about $1\%$ per year.

Which digestive enzymes are responsible for breaking down carbohydrates, fats, and proteins respectively?

Amylases (carbohydrates), Lipases (fats), and Proteases (proteins).

What lipoproteins are used to transport fats?

Chylomicrons, $VLDL$, and $HDL$.

Which macronutrient has the highest Thermic Effect of Food ($TEF$)?

Protein.

How do resistant starches and raw foods affect $TEF$?

They increase $TEF$ because the body must work harder to digest them.

How does exercise benefit older adults compared to young adults?

It lowers blood pressure, improves insulin sensitivity, preserves muscle mass, and maintains $BMR$, which is summarized as "Exercise is medicine."

What happens to fat cells when a person gains weight?

Fat cells enlarge and fat cell numbers increase.

Which change associated with fat gain is irreversible?

The increase in fat cell number; after weight loss, they shrink but do not disappear.

What are the roles of Leptin and Ghrelin in appetite regulation?

Leptin (produced in adipose tissue) signals fullness to stop eating, while Ghrelin (produced in the stomach) stimulates hunger.

How does sleep deprivation affect hunger hormones?

It increases Ghrelin and decreases Leptin, leading to greater hunger.

What is the formula for Body Mass Index ($BMI$)?

$$Weight\,(kg) + height\,(m)^2$$

Identify the $BMI$ categories for Underweight, Normal, Overweight, Obese, and Clinically Obese.

Underweight: Below $18$; Normal: $18-25$; Overweight: $25-30$; Obese: $30-35$; Clinically (morbidly) obese: Over $35$.

What are the limitations of using $BMI$?

It does not account for muscle mass, bone structure, or fat distribution.

How does gastric bypass surgery promote weight loss and what is a common side effect?

It reduces food intake and nutrient absorption by creating a small stomach pouch; it commonly leads to Vitamin $B_{12}$ deficiency.

What are the generic names for the $GLP-1$ agonists Ozempic, Wegovy, and Mounjaro?

Ozempic and Wegovy are Semaglutide; Mounjaro is Tirzepatide.

What hormones are targeted by Mounjaro (tirzepatide)?

$GLP-1$ and $GIP$.

How do $GLP-1$ medications reduce body weight?

They suppress appetite, slow stomach emptying, and improve insulin sensitivity.