Week 9 - Obesity

Question 1

How can we measure obesity?

Answer 1

BMI (Height (M^2 )/ weight (kg)
Between 18.5-24.9 is normal

Waist to hip ratio (more robust)

Question 2

Limitations of using BMI to measure health

Answer 2

-Bad measurement of muscle mass
- Someone healthy (eg athlete)
- doesn’t take in diet / ethnicity either
= not a measure of health, little predictive value to disease or mortality

Question 3

Implication of more than 48% of British being obese

Answer 3

Costs £16billion a year
525,000 hospital admissions for obesity related problems [2016/17]
6500 bariatric surgery (medically needed not cosmetic) [2016/17]

Question 4

Trend of gender and obesity

Answer 4

Increased prevalence in both genders but recently decreasing but predicted increase
Gender differences getting smaller / closer together
- Healthy school dinners , money put into health campaigns

Question 5

Explain Energy Intake vs Energy Output as a Biological Explanation for Obesity

Answer 5

Energy Intake vs Energy Output
- Adipocytes = fat cells , determined by childhood/genetic factors
greater number in obese individuals meaning energy input exceeds energy output (weight gain)

Question 6

Explain Basal Metabolic Rate as a Biological Explanation for Obesity

Answer 6

BMR = levels of energy needed to sustain normal functions of bodily systems
Low BMR = metabolise fewer calories for maintenance weight
High BMR = metabolise more calories for maintenance weight

Question 7

Explain genetics affecting obesity as a biological explaination

Answer 7

Concordance rate for obesity/BMI in Mz twins is 64-84% (Stunkard et al)
In different locations, twins had same predicted BMI = shows genetics are more important

Question 8

Explain the Set-Point Theory as a biological theory for obesity

Answer 8

Some individuals ideal biological weight falls in the obesity range
Each individual has an ideal biological weight (setpoint) - if weight departs from ideal , body takes corrective action (slow metabolism)
= predetermined

Question 9

Hormonal dysfunction as a biological theory for obesity

Answer 9

Adipocytes secrete leptin - signals hypothalamus to induce satisfaction
Some adipocytes don’t secrete enough leptin = never full enough so eat more

Question 10

Socioeconomic Status as a psychosocial theory for obesity

Answer 10

Relationship with Lower economic status and obesity
Poorer food choice / diet
Lower education = don’t know importance of healthy diet / exercise
Greater daily stress = weight gain

Question 11

Indirect and Direct stress as a psychosocial theory for obesity

Answer 11

Stress activates HPA axis (more cortisol)
= dysregulated metabolism = weight gain

Indirect : Negative coping behaviours = risk factor for obesity (sugars, smoking, alcohol)

Question 12

Cultural Factors as a psychosocial theory for obesity

Answer 12

Food industry spends £33bn per year on advertising
Exposure + TV ads correlate with BMI / Obesity (children especially)

Greater num of unhealthy food adverts per 20hrs TV = higher obesity
Greater num of healthy food adverts per 20hrs = lower obesity prediction

Triggers Automatic Eating

Question 12

Cultural Factors as a psychosocial theory for obesity

Answer 12

Food industry spends £33bn per year on advertising
Exposure + TV ads correlate with BMI / Obesity (children especially)

Greater num of unhealthy food adverts per 20hrs TV = higher obesity
Greater num of healthy food adverts per 20hrs = lower obesity prediction

Triggers Automatic Eating

Question 13

Body shape as an explaination for obesity

Answer 13

Apple shape vs Pear shape

Apple = more common in men , distribution of fat around chest = greater risk for problems (esp heart + brain inflammation)

Pear= more common in women, fat around buttocks = less obesity problem