Obesity Flashcards
What is the definition of obesity?
Excessive adiposity for the given age, gender, height, weight and ethnicity.
What are some Co-morbidities of obesity?
CVD, hypertension, diabetes type 1 &2 (reduced glucose tolerance, increased insulin production i.e. Hyperglycemia, insulin resistance, dyslipidaemia ( low HDL and high LDL, high cholesterol and TG), fatty liver, gallstones, infertility in women, varicose veins, peripheral oedema , osteoarthritis, spinal problems, hernias, incontinence, obstructive sleep apnea, cancer.
Define measures to classify risk of excess adiposity on the basis of fat distribution.
Waist circumference determines central adiposity, we also used to use waist: hip ratio, however it is not a great method to show small progress, since this ratio remains similar in most individuals even with weight loss.
Other possible answers not included in this lecture include: UWW, DEXA, Electrical bioimpedance, MRI, skinfolds, 3D scanning etc.
What are the limitations of BMI?
Main limitation of BMI: it can misclassify people who are perfectly healthy and fit (even above average) to be obese, because they have more weight from muscle mass. This applies to people who are professional bodybuilders, who are recreationally fit and athletes.
What are the recommended values of waist circumference for both females and males?
Men <102 cm, women< 88cm. With normal body mass. Although their effects on disease risks weakens to insignificant if the individual belongs to the overweight and obese weight categories. (Studies show same elevated levels of risk regardless of waist circumference for obese people.)
Describe the aetiology of obesity?
Causes of obesity include:
1)Energy imbalance. I.e. Energy consumed> energy used.
This imbalance can be caused by multiple reasons: emotions (emotional eating), environmental cues( clean vs. disorganized kitchen), food characteristics including how tasty they are, portion sizes and energy density, lifestyle behaviors (including sleeping duration and smoking), BMR, therm ic effects of food and activities of daily living, PA (duration, intensity and frequency, mode, how adapted you are you to that particular exercise), health status (if you are sick not likely to exercise as much), appetite and satiety.
2) genetics of obesity (mixed evidence, details of evidence refer to the lecture slides)
3) Environmental risk factors: availability of discretionary foods, remoteness (more rural areas mean less accessibility of healthy and fresh produce), low SES, menu labeling (more labeling means less over-consumption, vending machine intervention i.e with or without nutritional labels)
Explain the relationship between body mass, body fat and body fat distribution, and risk factors for certain diseases? Answer to be corrected.
Higher the body mass I.e. BMI, higher the disease risk. Low risks associated with underweight (but there are risks with other forms of diseases such as anorexia nervosa complications), average for normal weight, then MILDLY increased for pre-obese, and substantially increased for obese.
Higher the waist circumference, higher the disease risks.
Describe the prevalence of overweight and obesity in Australia including special sub-populations such as children and adolescents.
General qualitative trend: more prevalence for obese and overweight in males than females, but higher proportion of obese females within the whole female population. However, this does not mean that females do not have to worry as much as males regarding this issue. Because study have shown that females are more “at risk” than males, as well as males more “not at risk” than females.
Childrens have significant prevalence too. And around half of the parents underestimate their status, so this delays seeking help and exacerbate the issues. Also children in developed country belonging to low SES have greater prevalence.
Statistics: slide 16
Describe the components of daily energy expenditure.
Most of energy expenditure comes from BMR i.e energy our body needs to keep vital functioning going so we can survive. This is about 60-70%. Then the thermic effect of food i.e. Energy needed to digest which is about 10%. Then the variable parts are activities of daily living i.e. The energy we burn doing daily tasks, and then the structured, repetitive and planned exercises that health professionals suggest everyone to maximize.
Explain the RQ?
It is a fraction calculated by dividing co2 produced and o2 consumed. The result indicates whether the majority of energy provided to an individual originate from burning CHO (RQ approaches 1) or fat (approaches 0.7) or mixed diet (0.85).
A study suggests that a higher inherent RQ means the individual do not burn fat too much resulting in greater weight gain.
Describe current activities and sedentary behavior levels in Australia?
Only around half of Australians met the daily minimum requirement for 30 minutes of exercise per day, the other half have not met this. Physical activity remains similar across all SES, and is small proportional to the sedentary at work and leisure. Higher SES means more sedentary time spent at work.
The definition of obesity/overweight varies depending on ethnicity, gender,age and physical activity pattern. Give detailed descriptions of each.
1) Ethnicity:black women at higher death rate than white women, lower BMI for same risks of CVD and type 2 diabetes in Asian people.
2) Gender: women lower death rate.
3) Age: older people significantly higher death rate. But their BMI can be allowed higher than normal adults. ( graph on 9)
4) physical activity pattern: inactivity kills more than obesity. So even if you are normal weight, inactivity increases risk of diseases.
