The Disease of Human Obesity Flashcards
Eating behaviour, nutrient traffic and digestion are regulated by… (3)
- hormones
- secretagogues
- nervous system
What is a secretagogue?
What component of the nervous system stimulates or suppresses hunger signals?
Hypothalamic nuclei (feeding and satiety centres).
They receive many inputs from the GI tract, …
What factors determine how much a person will eat?
- Availability of food
- Characteristics of the food, stomach fullness or emptiness
- Current mass of the body fat compartment
- Physiological, psychological, habitual and social factors
When it is empty, the stomach releases…
ghrelin (orexigenic hormone)
Smaller adipose tissue stores leads to less secretion of…
leptin (absence of leptin stimulates hunger)
Leptin is a
a) anorexgenic hormone
b) orexigenic hormone
A physician’s inquire into eating habits can be organized into 3 areas
- hunger
- appetite
- satiety
Define hunger
Uncomfortable feeling with somatic characteristics: hunger pangs, restlessness, anxiety
Define appetite
Conscious yearning, typically for a specific food, with anticipation of hedonic pleasure
Define satiety
The feeling that enough food has been eating
True or false: People eat more in a social setting.
True
What is hedonic eating? Why do people eat more in a social setting?
Joy of eating?
What is obesity?
Disease that results from …?
BMI range for obesity
BMI 30-34.9: obese
BMI 35-39.9: very obese
BMI 40+: severely obesity
True or false: Typically, body fat goes up proportionally with BMI
True
True or false: Menstruating women tend to have a lower body fat than men
False: Menstruating women tend to have a higher body fat than men
What does a BMI of less than 20 tell us?
Fat compartment (body fat %) must be very low
BMI is very useful for…
rapid screening for obesity (but its limitations have to be appreciated and too often are not)!
BMI must be interpreted in the context of the physical examinations!
When is obesity a disease?
When it causes complications and pathologies, or substantially increase the risk of complications and pathologies (e.g. diabetes, HTN, CHF, etc).
Obesity is the disease brought about by excessive body fat, especially…
centrally distributed body fat
Features of metabolic syndrome
- abdominal obesity
- insulin resistance
- elevate BP
- abnormal plasma lipid profile
- ?
What is the waist-hip ratio?
A way to measure central fat distribution, an important predictor of the metabolic syndrome and higher disease risk (even in non-obese people).
3 rare causes of obesity (to be aware of and rapidly screen for)
- inherited metabolic disease
- insulinoma (tumour)
- hypothalamic lesion
Common causes of obesity
Does a low metabolism cause obesity?
In general, no. The resting metabolic rate of obese people is almost always greater than that of non-obese people.
How can obesity increase energy expenditure?
Remember the RMR comes from the body cell mass. At very high BMIs, % of body fat appears to stop increasing.
In fact, muscle mass increases to carry all that extra weight (from fat) increasing the RMR.
Obesity predisposition is strongly heritable, but obesity develops only under certain conditions:
- habitual overconsumption of inexpensive, appetizing, low-bulk, highly-refined carbohydrate foods
- habitual continuous sipping, nibbling, …
50% of total food energy intake in Canada comes from…
ultra-processed foods
What is the thrifty gene hypothesis
That evolution has designed us to enjoy eating food, and a lot of it, when it is available; we have a capacity to survive famine.
Why isn’t everyone obese?
Obesity is precipitated by
* genetic predispositions
*obesogenic environment
we don’t know why some of these people are resistant to obesity
What type of drugs can combat obesity? Briefly describe how they work
GLP1 antagonists
