Lab Body Composition

Question 1

What is body composition?

Answer 1

The relative proportion of fat and fat-free tissue in the body.

Question 2

What is sarcopenia?

Answer 2

Age-related loss in muscle mass and accompanying strength.

Question 3

What happens to the body composition as a result after 30?

Answer 3

The weight may stay the same but the composition is different as there is a gradual loss of muscle and an increase in fat leading to weight gain.

Question 4

What is the upper limit for recommended percent body fat levels for adults and children in the age bracket of 18-34?

Answer 4

22 percent (High), >22 percent (Obesity)

Question 5

What is the upper limit for recommended percent body fat levels for physically active adults in the age bracket 18-34?

Answer 5

15 percent

Question 6

What are the false assumptions in the weight loss process?

Answer 6

Lean body mass is not going to change when someone is losing weight, which is not true. The greater the rate of weight loss the greater percentage of weight loss is lean tissue.

Question 7

What is the ideal and healthy rate of weight loss per week?

Answer 7

.5-2.2lb per week.

Question 8

What is the effect of Yo-Yo crash diets with weight regained on RMR?

Answer 8

Resting metabolic rate is dependent on lean mass, whereas in Yo-Yo diets the majority of weight loss is lean mass. So the body composition can significantly change to a higher percent of fat than lean mass even at the same weight.

Question 9

With an increase in body mass index, this will also lead to an increase in what?

Answer 9

An increase in all-cause mortality as BMI gets higher.

Question 10

Although there are multiple Body Comp Models, what is the key variable and how are they separated?

Answer 10

All Body Comp Models separate Fat Mass and varying complexities of Fat Free Mass.

Question 11

What is the calculation formula for weight to lose to get to specific % of body fat?

Answer 11

Desired weight = Lean Body Mass/Desired Lean %

Question 12

BMI is a measurement of what?

Answer 12

The measurement of BMI does not yield %fat, therefor is not a measurement of body composition. Rather, it is a modified height-to-weight ratio.

Question 13

What is the main downfall of using BMI as a measurement of body comp?

Answer 13

It is assumed that an increase in BMI, means an increase in overall Body Composition. However, it does not take into account the possible addition of muscle mass.

Question 14

What is the BMI formula?
What are the typical BMI ranges?

Answer 14

BMI = wt(kg)/Ht(m^2)

Normal: 18.5-24.9
Overweight: 25-29.9
Obese: >/=30

Question 15

What is the only way to EXACTLY determine body comp?

Answer 15

Technically, the only way to determine body composition exactly is through chemical dissection which can only be performed if an individual is dead.

Question 16

Name at least 3 methods for estimating Body Composition?

Answer 16

• Anthropometry
  -BMI
  -Bioelectrical Impedance Analysis (BIA)
  -Skinfold
  -Plethysmography
  -Underwater Weighing
  -Total Body Water
  -Ultrasound
  -Dexa
• See Slides for more examples

Question 17

What is tissue heterogeneity?

Answer 17

Meaning essentially the diversity of tissue. “Fat Mass” is not 100% fat; Adipose tissue is a mixture of fat, water, and protein, while fat free mass is more complex.

Question 18

What 2 test are the “Gold Standard” for Body fat assessment and what are their standard margins of error?

Answer 18

• Dual-energy X-Ray absorptiometry
  +/- 1.8%
• Underwater Weighing
  +/- 2.5%

Question 19

What is the dependence of the BIA test?

Answer 19

The BIA measures resistance through the current through estimated Total Body Water which is easily affected by hydration status.