Obesity and Cancer Flashcards
1
Q
Obesity
- what is it
- what it is related to
A
- Is a condition where the natural energy reserve, stored in the fatty tissue of humans, is increased to a point where it is thought to be a significant risk factor in certain health conditions, leading to increased mortality
- excessive body weight shown to correlate with various diseases, particular cardiovascular disease, diabetes, sleep apnea and osteoarthritis.
- also considered risk factor for certain cancers
2
Q
Energy balance
-what it is
A
- energy intake and output normally balanced under steady-state conditions
- only about 27% of energy ingested in food is used for functional purposes
- excess energy stored as fat*food intake is regulated in accordance with body’s needs.
- body has powerful control systems to avoid a deficit (weaker systems to control an excess)
- due to history
3
Q
BMI
A
BMI = mass(kg)/height^2 (m^2)
4
Q
Prevalence of obesity over time
A
- has increased over time
- especially since 1980s due to emergence of fast food chains and the microwave
5
Q
Obesity types (males and females)
A
- Is visceral and subcutaneous fat
- Men tend to have more visceral fat than subcutaneous fat
- women tend to have more subcutaneous fat
*visceral is more dangerous
6
Q
BMI -> problems
A
- BMI is most widely accpeted calculation
- Has no meaning by itself
- cannot distinguish between fat mass, muscle mass or bone mass
- muscle is more dense than fat
- children have higher bone density = false BMI
- muscular atropy/osteoporosis in elderly isn’t accounted for
- Caucasian women have less muscle mass and bone density than men of same height
7
Q
Alternative ways to measure body fat
A
- % body fat
- for men, >25% is bad and women > 30% obese
- Underwater weighing (fat floats)
- Skinfold test (thickness of subcutaneous layer)
- Bioelectrical impedance (metal footpads that send small current through body)
8
Q
Evolutionary aspects
A
- Food scarcity; take advantage of rare periods of abundance by storing energy
- is an evolutionary advantage = thrifty phenotype
- this is maladaptive in modern society with adequate food supplies
- many people have genetic propensity towards obesity, but this propensity requires a modern environment;
- increased food availability
- decreased requirements for physical labour
9
Q
Society’s flaws in promoting obesity
A
- lack of activity (due to modern convenience)
- lower relative cost of foodstuff
- increased marketing
- 2 income households
- microwave oven
- increased no. of fast food outlets
- increasing affluence itself
- aging population (older ppl have slower metabolism)
10
Q
Specific causes of obesity
A
- sedentary lifestyle
- high lycemic diet
- underlying illness
- genetic disorder
- psychological eating disorders
- stress
- psychotropic medications
- smoking cessation
11
Q
Energy availability in foods
-proteins, carbohydrate and fat
A
1 g protein = 16.7kJ
1 g carbohydrate = 16.7kJ
1 g fat = 37.7 kJ
-Carbohydrate and protein usu. associated with large volumes of water in foodstuffs (75%), whereas fat is not
-fat is hydrophobic - doesnt associate with water
12
Q
Endocrine mechanisms
A
- hormonal mechanisms have been shown to control appetite and food intake, storage patterns of fat and development of diabetes
- Leptin is produced by fat tissue to signal storage reserves in the body, and mediates long-term appetitive controls
- Ghrelin, produced by stomach, modulates short-term appetite control (obese ppl don’t respond well to Ghrelin, as non-obsese ppl)
- many also thought to be leptin-resistant
13
Q
Complications with Obesity
A
- Cardiovascular
- endocrine
- gastrointestinal
- Renal and genitourinary
- skin and appendages
- musculoskeletal
- neurologic
- respiratory
- psychological
14
Q
Therapy
3
A
- Best treatment = energy-limited diet and increased exercise
- as little as 5% loss of body mass = enormous health benefits
- 80-95% of ppl regain weight in 2 to 5 yrs
- is brain plasticity problem -> brain recognises weight as desired weight - results in yo-yo dieting
- after weight loss, need to reset brain pathways
- is brain plasticity problem -> brain recognises weight as desired weight - results in yo-yo dieting
-Also pharmacotherapy and bariatric surgery (staples)
15
Q
Cancer
A
- is a class of diseases characterised by uncontrolled cell division and the ability of these cells to invade other tissues
- is caused by damage to DNA, resulting in mutationss to genes that control cell divison
- Mutations can occur spontaneously, caused by chemicals or physical agents called carcinogens, exposure to radioactive materials or can be passed down generations
