Physical activity, obesity and weight control

Question 1

What is an adipose cell?

Answer 1

One giant lipid droplet and a very small cytosol

Question 2

What is the role of an adipose cell?

Answer 2

highly specialised tissue in energy storage

plastic (can adapt and expand a lot)

Question 3

What is hyperplasia?

Answer 3

Number of fat cells

Question 4

What is hypertrophy?

Answer 4

Size of fat cells

Question 5

Within the normal range body fat stores, what explains changes in fat mass?

Answer 5

Increased size of adipocytes

Question 6

Within the high range body fat stores, what explains changes in fat mass?

Answer 6

Increased number of adipocytes

Question 7

What happens to obese adipose tissue? (4)

Answer 7

• becomes dysfunctional
• increase in white blood cells
• changes in tissue production
• affects all of the cell in the body

Question 8

Where is situated subcutaneous fat?

Answer 8

between the skin and abdominal muscles

Question 9

Where is situated visceral fat?

Answer 9

under abdominal muscles

Question 10

What are the comments of Foster et al (2012) on phenotypes?

Answer 10

Phenotypes are very important for health

The way fat is stored is as imported as whether fat is stored at all

Question 11

What is the effect of obesity in leptin and adiponectin production?

Answer 11

• increase in leptin production

- decrease in adiponectin production

Question 12

In the UK how many females >45 y/o are overweight or obese?

Answer 12

Over 3 quarters

Question 13

How are overweight and obesity defined on the BMI scale?

Answer 13

overweight: 25.0 - 29.9 kg/m2
Obesity: >30 kg/m2

Question 14

What are DEXA scans useful for? (2)

Answer 14

• can characterise total fat mass and fat location

- can monitor changes in adiposity and distribution

Question 15

What is weight circumference measurement?

Answer 15

A measure of visceral adipose tissue expansion

Question 16

What is hydrostatic weighing?

Answer 16

• A measure of body fat
• Relies on the estimation of body density (mass/volume)
• Then uses the Siri equation to estimate percentage of body fat (% body fat = 495/density - 450)

Question 17

How does hydrostatic weighing determine body volume?

Answer 17

Measure difference between weight on land and in water

Estimate body volume from loss of weight

Question 18

What are some temporal considerations of weight gain? (3)

Answer 18

• Energy intake has been greater than output over a long period of time in entire populations
• Energy surplus in the past followed by energy maintenance: weight gain is never lost
• Chronic small differences

Question 19

What is the most malleable factor of TEE between BMR, DIT and PAEE

Answer 19

Physical Activity Energy Expenditure

Question 20

What does Thompson et al. (2009) state about PAEE?

Answer 20

PAEE explains the variance in TEE between individuals

While BMR and DIT do not vary significantly between individuals

Question 21

What is the Turner et al. (2010) study?

Answer 21

• 6 months structured exercise intervention in middle aged men
• prescribed exercise increased total PAEE and doesn’t affect non-prescribed PAEE
• but 50% less weight loss than anticipated
• effect of compensation: 100kcal/day increase in EI

Question 22

How can TEE be estimated?

Answer 22

• accelerometers
• doubly labeled water
• combination of activity diaries and whole-body calorimetry

Question 23

What is a practical issue of standard exercise interventions which result in relatively low increases in TEE?

Answer 23

• noise in measurement of TEE
• tools are not sufficiently sensitive to capture relatively small increases in TEE over the course of a typical exercise intervention

Question 24

What is the effect of substitution?

Answer 24

if exercise is prescribed during a time of the day with high non-prescribed PAEE, then the energy deficit might be low or even null (Turner et al. 2010)

Question 25

What is the effect of compensation?

Answer 25

• prescribed exercise can negatively affect non-prescribed PAEE (Thivel et al. 2013)
• prescribed exercise can result in increased energy intake resulting in lower weight loss than anticipated (Thompson et al. 2014)

Question 26

What temporal considerations does Hall et al. (2011) mention?

Answer 26

weight loss is never linear

theoretical weight loss will always stall because loss of mass decreases BMR

Question 27

Maria Brandkvist et al. (2019) and Walter et al. (2016) both state a modern issue with weight gain, what is it?

Answer 27

Genes linked with higher obesity risk
Gene predispositions for weight gain have always existed
However, modern environment has exposed the effect of these genes

Question 28

What does the Frayn K (1996) study state about the role of genetics?

Answer 28

Slow metabolisms don’t exist, in fact the heavier you are, the higher your BMR

Question 29

What does the Stunkard et al. (1986) state about the role of genetics?

Answer 29

Compared adoptive children’s genotype with their birth and adoptive parents’ genotype
Found evidence of correlation between birth parents’ genotype and children’s regarding risk of obesity but not with adoptive parents

Question 30

What is the effect of genotype on obesity risk?

Answer 30

Genotypes may increase the likelihood of becoming overweight or obese through a predisposition for energy imbalance

Question 31

What novel argument does Ortega et al. (2019) propose?

Answer 31

Fitness is more important than fatness in terms of CVD risk

low fit + low fat is more dangerous then high fit + high fat

Question 32

What is the risk of excess adipose tissue?

Answer 32

Excess adipose tissue increases the risk of chronic diseases (especially abdominal or central adipose tissue)

Question 33

What is a decrease in adiponectin associated with? (2)

Answer 33

• insulin resistance

- atherosclerosis

Question 34

What do leptin levels correlate with?

Answer 34

energy stores