Body Composition

Essential Fat

Fat that is essential for normal physiological function.

Where is essential fat present?

Nerve tissues, bone marrow, and organs (all cellular membranes).

Essential Fat Amount for Men

~3% of body mass.

Essential Fat Amount for Women

~12% of body mass (5-9% of that is sex-specific fat).

What does storage fat represent?

An energy reserve.

One pound of storage fat =

~3500 kcal.

Storage fat increases when…

More energy (kcal) is ingested than expended.

Storage fat decreases when…

More energy (kcal) is expended than consumed.

Storage fat can be deposited subcutaneously, just below the…

Skin or deeper layers of tissue.

% of adipose tissue made of triglycerides?

96%

Composition of adipose tissue:

~83% pure fat

~15% water

~2% protein

Fat deposition

A natural process when one consumes more calories than they expend.

What are the two general genetic trends in the body areas where fat is deposited?

Central (android) and peripheral (gynoid) fat deposition.

What shape is central fat deposition?

Apple shape.

In central fat deposition, most adipose tissue is deposited around the…?

Abdomen and thorax.

In central fat deposition, fat may be stored in the…?

Subcutaneous tissue or wrapped around abdominal organs.

Subcutaneous adipose tissue (SAT)

Layer of fat just below the skin.

Visceral adipose tissue (VAT)

Visceral fat surrounding abdominal organs.

Central Fat Deposition may contain a high amount of…?

Visceral fat.

A high level of visceral fat increases risk of?

Heart disease and type II diabetes.

What shape is peripheral fat deposition?

Pear shape.

In peripheral fat deposition, most adipose tissue is deposited around the…

Buttocks and upper thighs.

Height/Weight Chart

Developed by insurance companies to track growth. Does not measure fat.

Body Mass Index (BMI)

A measure of height vs. weight. BMI = kg/m². Used internationally.

Girth measurements

Measures circumference of body parts.

BMI Formula

Mass (kg) / Height (m²)

Adults with a >25 BMI are identified as…

Fat-loss candidates.

BMI is a good tool to examine…

Large populations.

The American Medical Association (AMA) suggests that BMI should be used in conjunction with…?

Waist circumference, waist-to-hip ratio, and direct body fat measurement.

Body Composition

Percentage of body mass that is fat vs. fat free.

Two compartment model

Includes fat mass and fat-free mass.

Fat Mass

Essential and storage fat.

Fat Free Mass

Protein, bone (Ca + Ph) and other elements (Mg, Na, K, Cl).

Anatomical model

Adipose tissue, muscle, organs, bone.

Chemical model

Fat, protein, carbohydrates, water, mineral.

Field Tests Used to Determine Fat

Skinfold measures, bioelectrical impedance analysis (BIA), and near infrared interactance (NIR).

Skinfold Measures

Measures subcutaneous fat. Good for observing fat loss/gain.

Bioelectrical Impedance Analysis (BIA)

Measures impedance to electrical current; the body’s conductivity.

Near-Infrared Interactance (NIR)

Infrared light passes through muscle and fat at different frequencies of light spectrum.

Dual-energy X-ray absorptiometry (DEXA, DXA)

Uses a little radiation to determine density of bone. Calculates tissue and fat content. Gold standard.

Hydrostatic Weighing

Method of measuring body fat by comparing weight on land and underwater.

Air Displacement Plethysmography (BOD POD)

Measures volume of air displaced to determine density of fat vs. lean mass.

Overweight

When body mass is greater than normal.

Over fat

When percentage of weight that is fat is greater than normal.

Obesity in female adults:

>35% of body mass is adipose tissue.

Obesity in male adults:

>25% of body mass is adipose tissue.

Pre-clinical obesity

Elevated risk of future health issues.

Clinical obesity

A chronic disease with organ dysfunction.

Morbid obesity is when…

Fat ≥ 50% of body mass is adipose tissue.

Cardiometabolic Syndrome

A cluster of conditions that occur together, increasing the risk of various health problems (heart disease, diabetes, cancer, etc.).

When one gains fat, there is an _____ of storage adipose cells.

Hypertrophy.

When one loses fat, there is an _____ of storage fat adipose cells.

Atrophy.

Leptin

A hormone that induces feeling of satiety (fullness). It inhibits appetite.

Ghrelin

A hormone that makes us feel hungry when leptin is not blocking ghrelin receptors in the brain.

Semiglutide

A glucagon-like peptite-1 receptor agonist (GLP-1 RA) that mimics GLP-1 hormone, produced in small intestine. (AKA Ozempic, Wegovy, Rybelsus).

GLP-1 prompts pancreas to produce more…

Insulin → Reduction of blood glucose → Used to treat type 2 diabetes.

General goal of fat loss lifelong behavior strategy:

Maintain lean body mass and decrease fat mass.

Energy stored =

Energy input ± Energy output

Where is excess caloric intake stored?

In adipose tissue as storage fat.

ASCM caloric intake recommendations

Reduce energy intake to 1000-2500 kcal/day.

Eat nutrient dense, caloric poor foods.

Nutrient dense, calorie poor diet

High complex CHO (fruit, vegetables, whole grains), low fat.

Low calorie diet

Low fat content, especially animal fat; low in junk food.

Ultra processed foods (UPF)

~60% of typical US diet comes from UPF.

UPF increases risk of…

Cardiometabolic syndrome, cognitive decline, depression, and anxiety.

Clinically significant fat loss amount of physical activity per week

>250 min/week

Progressive overload for fat loss via aerobic exercise (ACSM Exercise Recommendation)

Intensity (light-moderate): 55-69% of maximal heart rate.

Duration: ≥40-60 min/day ≥ 250 min/week

Frequency: 5-7x a week

Resistance training (ACSM Exercise Recommendation)

2-3x a week for resistance training.

Exercise recommendations for fat maintenance (ACSM Exercise Recommendation)

Exercise at least 150 min/week, better if 250 min/week for fat maintenance.

Dr. Bob Gutin’s Hypothesis states that:

Vigorous activity in children and adolescents has inverse relationship to adiposity.

During low intensity exercise, mostly _____ are used to resynthesize ATP.

Triglycerides.

During high intensity exercise, mostly _____ are used to resynthesize ATP.

Carbohydrates.

Which burns more calories: Aerobic or Anaerobic Exercise?

Aerobic exercise.

What type of training has the potential to increase lean body mass?

Resistance training due to increased basal metabolic rate.

What is a limiting factor in training?

Time.

Crash dieting

Drastic decrease in calorie intake → body in starvation mode → decrease in basal metabolic rate → less calories burned for survival → little fat loss.

Yo-yo dieting

Regularly on-and-off dieting. Body sends message that starvation is regularity → basal metabolic rate gets stuck at starvation mode.

Fad diets

Popular diet for short amount of time without being a standard scientific dietary recommendation.

Zone & Atkins diet

High protein, low CHO diet.

Nutrient poor, large water loss, more kcal burned during eating, difficult to eat large amounts of protein regularly.

Rubber (plastic, sauna) suits

Leads to initial water loss due to excessive sweating, no loss of fat.

Spot reducing

Targeting exercise for muscles in a given body part for fat loss in that body part.

Body image

What one thinks and feels about their appearance and how they judge their own self-worth.

Anorexia nervosa

Self-imposed starvation in an effort to lose weight and achieve thinness.

Bulimia nervosa

Binge eating followed by one or some combination of self-induced vomiting, intense exercise, use of laxatives or diuretics (purging).

Female Athlete Triad

3 interrelated disorders of disordered eating, menstrual dysfunction, and eventual bone mineral disorders.

Female Athlete Triad leads to…

Disordered eating → menstrual disturbances/amenorrhea → over time bone loss due to low calcium levels → premature osteoporosis.

Male Athlete Triad

1. Energy deficiency →

2. Reproductive suppression (low testosterone, oligospermia, reduced sex drive) →

3. Poor bone health

Muscle dysmorphia

Altered self-image where someone believes their muscles are smaller than they actually are. As a result, they used ergogenic substances and resistance training to increase muscle size.

Weight cutting

Practice of rapidly losing body mass over a few hours to several days.

Common methods of weight cutting

Food restriction, water loading, increased training or energy expenditure, sauna use, sweat suit use.

Weight cutting decreases…

Dehydration, lean body mass, testosterone concentration, immune function, and muscle + liver glycogen content.

Weight cutting performance side effects

Decreased aerobic, muscular, speed, and power endurance. Decreased coordination.