Obesity Flashcards
What BMI values define the following:
- underweight
- healthy weight
- overweight
- obese
- sever obesity
underweight
healthy 18.5 - 24.9
overweight 25 - 29.9
obese 30 - 39.9
severe obesity 40+
How do we calculate BMI?
BMI = weight (kg) / height 2 (m)
List 4 beneifts of losing weight for an individual who is above the ‘healthy’ BMI
Improve life expectancy
↓ risk of heart disease, stroke, type 2 diabetes, some cancers
↓ risk/ Improve lower back and joint pain
↓ risk of fertility problems
List 4 comorbidities associated with obesity
(Incl atleast one metabolic, mechanical, mental)
Why obesity associated with/ an increased risk of comorbidities?
Adipocytes in people with obesity release factors that cause widespread inflammation
How does obesity leads to cardiovascular disease?
- ↑Endothelial permeability, plaque development, atherosclerosis
- ↓Cholesterol metabolism, ↑glucose production, insulin resistance
How does obesity leads to Type 2 diabetes?
- ↓Cholesterol metabolism, ↑glucose production, insulin resistance
- ↓ Glucose uptake, insulin resistance
- ↓Insulin secretion
What is leptin and where is it released from?
Hormone released from adipocytes into the blood - functions to suppress appetite
What is congenital leptin deficiency?
A condition that causes severe obesity beginning in the first few months of life due deficiency in leptin
How would a baby with congenital leptin deficiency appear at birth?
How and why does this change as they age?
At birth → normal weight
After weaning, they experience hyperphagia (no food preference)
Results in dramatic weight gain → increased fat mass (57%) BUT normal height
Is congenital leptin defiency associated with defects in BMR or energy expenditure?
NO - there is no defect in BMR or energy expenditure
How does congenital leptin deficiency affect sexual development and function?
CLD is often a/w hypogonadotropic hypogonadism (↓ production of sex hormones)
Thus individuals do not undergo puberty and may be infertile
Can be managed with appropriate treatment
How does congenital leptin deficiency affect immune function and why?
Impaired immune function
Leptin regulates the innate and adaptive responses through modulation of immune cells survival, proliferation and activity
How is congenital leptin deficiency treated?
Daily leptin therapy
Other pathological causes of childhood obesity may be related to defects in what pathway?
List 2 examples in this pathway
The leptin– melanocortin pathway
Eg. POMC deficiency, Sim-1 deficiency
List 4 other discrete disorders which cause obesity
- Cushings syndrome
- Hypothyroidism
- Prader-Willi syndrome
- Polycystic ovary syndrome
Peripheral signals from the gastrointestinal tract regulate _____ and _____ homeostasis
List 4 examples + which part of the GIT each comes from
energy, glucose
- CCK - Duodenum
- Ghrelin - Duodenum and stomach
- Insulin and glucagon - Pancreas
- Peptide YY - Jejunum, Ileum and colon
What hormone is found to be low in adults and children with obesity?
Where does this hormone come from and where does it act?
Peptide YY
Secreted from the Jejunum, Ileum and colon and acts upon key brain areas that control eating and reward
What is Ghrelin?
“Hunder hormone” - increase hunger and caloric intake
Graph shows ‘pre-meal’ surges of ghrelin
Explain the pathway of how feeding behaviour is regulated
What gene varient has recently been discovered, that predisposes and individual to diabetes
How is this thought to occur?
FTO gene (a/w diabetes and childhood and adult obesity due to its affect on BMI)
FTO genetic variant causes a failure to suppress hunger and ghrelin after eating resulting in:
- Increased food intake (energy-dense foods)
- Increased appetite
Discuss how the biology of a person with obesity changes and how this predisposes them to further weight gain
Discuss the 3 management options for an overweight or obese individual
Conservative → non-conservative
- Diet, physical activity and behaviour therapy
- Pharmacotherapy
- Bariatric surgery
What is the only pharmacotherapy licenced for use in the UK
How does it work and to whom is it prescribed?
Orlistat - works by preventing ~1/3 of the fat consumed in food from being absorbed
Prescribed for individuals with a BMI ≥ 28 and for other weight related conditons (ie ↑BP, type II diabetes)
What advise must be given to patients using Orlistat
Treatment with Orlistat must be combined with a balanced low fat diet, increased excerise and other weight loss stratagies
Which individuals may be elligible for bariatric surgery?
- BMI >35 with co-morbidities
- BMI > 40
Bariatric surgery is associated with sustained weight loss over 20 years, improved health and survival - it is very effective
What lifestyle recommendations would you give to an overweight patient regarding nutrition, activity and behaviour therapy?
Why may an individual regain more weight than originally lost following a diet
Dieting and weight loss puts the body in a mode of famine/starvation
This activates powerful compensatory biological changes
Resulting in ↑hunger, ↑energy expenditure and ↑interest in food
Maintenance of lifestyle induced weight loss is challenging
