Body composition

Question 1

What is body composition?

Answer 1

The relative proportions of protein, fat, water and mineral components in the body that make up the total body weight.
Made up of fat mass and fat free mass.

Question 2

What is the difference between assessing body weight and body composition?

Answer 2

Body weight = total weight of fat free mass and fat mass combined
Body composition = assessment of the varying components of the FFM compared to the FM

Question 3

What are the constraints of BMI?

Answer 3

Does not take body composition into account
Should be used in conjunction with other measures (e.g. waist circumference)
Different classifications for different ethnicities

Question 4

What are alternative measures of height?

Answer 4

Ulna length
Knee height caliper
Demi span

Question 5

What is an alternative measure of weight?

Answer 5

Middle upper arm circumference
<23.5cm indicates BMI <20kg/m2
>32cm indicates BMI >30kg/m2

Question 6

What measures are used to assess body composition?

Answer 6

Anthropometry

Densitometry

Question 7

What measures are used to assess body composition?

Answer 7

Anthropometry
Densitometry (measure of bone density)
Bioelectrical impedance
Imaging techniques

Question 8

How is anthropometry used to assess body composition?

Answer 8

Skin folds used to estimate volume of subcutaneous fat

Question 9

What are the limitations of using skin folds to assess body composition?

Answer 9

Assumes a constant ratio of subcutaneous and total fat.

Sensitive to ethnic and age variations in fat distribution.

Question 10

How is densitometry used to assess body composition?

Answer 10

Under water weighing measures % body fat

Question 11

How does bioelectrical impedance work to assess body composition?

Answer 11

Works on the premise that fat does not contain water so electrical current flows through the tissues containing water and ions but not fat

Question 12

What are the limitations of bioelectrical impedance?

Answer 12

Error on data entry 
Requires standardised conditions 
Assumes hydration of FFM is constant 
Affected by skin temperature 
Can't use in dehydration, ascites or extremes of BMI

Question 13

What is malnutrition?

Answer 13

Refers to both over and under nutrition.
Deficiency or excess of energy, protein and other nutrients causes measurable adverse effects on tissue/ body form, function and clinical outcomes.

Question 14

What chronic diseases/ clinical outcomes are associated with over nutrition?

Answer 14

Pulmonary disease
Sleep apnoea 
Coronary disease
Type 2 diabetes 
GI diseases
Cancer
Depression
Stroke 
Non-alcoholic fatty liver disease

Question 15

What is cachexia?

Answer 15

Condition of abnormally low weight, weakness and general bodily decline associated with chronic disease.
Associated with loss of skeletal muscle rather than body fat.
Symptoms include: weight loss, muscle atrophy, fatigue, weakness, loss of appetite.

Question 16

What factors affect body composition?

Answer 16

Biological (age, gender, ethnicity, genetics)
Lifestyle (diet, physical activity, smoking)
Health-related factors (disease, genetic disposition)
Biometric (height, fat and muscle distribution)
Environment

Question 17

How can food be used as an energy source?

Answer 17

Metabolised by KREB (Citric Acid cycle) to make ATP

Question 18

What does basal metabolism rate control?

Answer 18

Body temperature

Autonomic functions

Question 19

What are the 6 essential nutrients we need to survive?

Answer 19

Water
Calories (e.g. from carbohydrates and fat) 
Protein 
Essential fatty acids
Vitamins 
Minerals

Question 20

What are the functions of carbohydrates?

Answer 20

Energy source (50-75% of our energy comes from carbs) 
Increase blood glucose levels

Question 21

What are the functions of proteins in our diet?

Answer 21

Growth and repair

Supply 10-20% of energy in our diet

Question 22

What are the functions of fat in our diet?

Answer 22

Healthy skin and hair
Insulating body organs from shock 
Maintaining body temperature 
Promoting healthy cell function 
Storage of vitamins

Question 23

Where in our diet do we get Vitamin A and what is its function?

Answer 23

Fish oil and green veg

Eyesight, growth, infection

Question 24

Where in our diet do we get B vitamins and what are the collective functions?

Answer 24

Peas, grains, dairy, meat, fish, egg, green veg

Metabolism, Nucleic acid synthesis

Question 25

Where in our diet do we get Vitamin C and what is its function?

Answer 25

Peppers, spinach, citrus fruits | Cartilage and bones

Question 26

Where in our diet do we get Vitamin D and what is its function?

Answer 26

Sunlight, eggs, butter | Calcium and phosphorus metabolism

Question 27

Where in our diet do we get Vitamin E and what is its function?

Answer 27

Vegetable oil | An antioxidant

Question 28

Where in our diet do we get Vitamin K and what is its function?

Answer 28

Vegetables, fruit | Clotting

Question 29

Where in our diet do we get Iron and what is its function?

Answer 29

Red meat, fortified cereals, green leafy vegetables | Component of Hb for oxygen transport

Question 30

Where in our diet do we get Calcium and what is its function?

Answer 30

Milk | Bones and teeth; nerve and muscle function

Question 31

Where in our diet do we get Zinc and what is its function?

Answer 31

Meat, seafood, wholegrains | Enzymes, immune system

Question 32

Where in our diet do we get Magnesium and what is its function?

Answer 32

Meat, dairy, green veg, nuts | Metabolism; nerve and muscle function

Question 33

Where in our diet do we get Potassium and what is its function?

Answer 33

Fruit and veg | Fluid balance; nerve and muscle function

Question 34

What are the time limits for fed, fasting and starved states?

Answer 34

``` Fed = 0-4 hours after food Fasting = 4-12 hours after food Starved = 12+ hours after food ```

Question 35

Where does your body get energy from when in a fasting state?

Answer 35

Glycogen stores broken down into glucose to supply brain, nervous system and blood cells (+ other cells) Body fat stores broken down into fatty acids to provide energy to other cells

Question 36

Where does your body get energy from when in a starved state?

Answer 36

Body protein broken down into amino acids which are then broken down into glucose and ketone bodies: Glucose provides energy to the brain, nervous system and blood cells (+ other cells) whilst ketone bodies provide energy to other cells of the body Body fat stores are broken down into fatty acids which provide energy to other cells and ketone bodies which provide energy for the brain, nervous system and blood cells