Obesity & weight loss management 5.3.1 Flashcards
1
Q
What is obesity?
What are the classes?
A
- BMI >30kg/m2
- Class I- 30-34.9kg/m2
- Class II- 35-39.9kg/m2
- Class III- >40kg/m2 (severe, extreme, massive obesity)
- waist circumference
- measure in addition to BMI to measure abdominal obesity
- ≥102 cm for men
- ≥88 cm for women
- Is considered elevated and indicative of increased cardiometabolic risk
- Especially in BMI 25-35kg/m2
2
Q
What are some causes of obesity?
A
- regulation of body weight
- complicated feedback systems–> changes in appetite, energy intake & energy expenditure
- excess weight in individuals usually results from a prolonged period of energy imbalance but the causes of overweight and obesity are complex
- diet & physical activity are central to the energy balance equation but are influenced by:
- social
- environmental
- behavioural
- genetic
- physiological factors
- the relationships between which are not yet fully understood
- individuals may be at greater risk of weight gain at particular stages in their lives
3
Q
What are some OTHER causes of obesity?
A
- Sedentary lifestyle and increased caloric intake are usually the key contributing factors (but do consider secondary causes)
- iatrogenic
- Medication
- Hypothalamic surgery
- dietary
- Overeating
- High-fat diets
- Frequency of eating
- Progressive hyperplastic
- obesity
- Infant feeding practices
- neuroendocrine
- PCOS
- Hypothyroidism
- Hypothalamic obesity
- Cushings
- Seasonal affective disorder
- GH deficiency
- social & behavioural factors
- Socioeconomic status
- Ethnicity Psychological factors
- Binge eating
- Night eating syndrome
- sedentary lifestyle
- Enforced (eg post-op)
- Aging
- genetic obesities
- Autosomal traits
- Chromosomal abnormalities
- other
- low birth weight
4
Q
What to consider with investgating the cause of obesity?
A
- To determine aetiology and plan future management strategies, additional medical history should:
- Include age at onset of weight gain
- Events associated with weight gain
- Previous weight loss attempts
- Change in dietary patterns
- History of exercise
- Current and past medications
- History of smoking cessation
5
Q
What are some common medications associated with weight gain at 12 weeks from commencement?
A
- atypical antipsychotics for BPAD
- clozapine, olanzapine
- beta adrenergic blockers for HTN, anxiety
- esp propanalol
- insulin for DM
- lithium for BPAD
- pizotifen for migrane and cluster headache
- sodium valproate for epilepsy and psychosis
- sulphonylureas for T2DM
- chlorpropamide, glibenclamide, glimepiride, glipizide
- pioglitazone for T2DM
- TCAs for depression
- amitriptyline
- anabolic steroids
- various endocrine disorders
6
Q
Which drugs can produce weight loss?
A
- anticonvulsants
- topiramate, zonisamide, lamotrigine
- antidepressants
- bupropion, venlafaxine, desvenlafaxine
- antipsychotics
- ziprasidone
7
Q
Which drugs can produce weight gain?
A
- antidepressants
- MAOS
- TCSa- nortriptyline, amitriptyline, doxepin
- paroxetine, citalopram, escitalopram, imipramine, mirtazapine
- antipsychotics
- olanzapine, risperidone, clozapine, quetiapine
- diabetes meds
- insulin, sulfonyureas, thiazoidediones, meglitinides
- glucocortisosteroids
- prednisone
- anticonvulsants
- mood stabilisers
- lithium, carbamazepine, gabapentin, valproate
8
Q
Can smoking cessation contribute to weight gain?
How to not gain weight?
A
- yes
- People who quit smoking for at least one year experience greater weight gain and increased waist circumference than those who continue to smoke
- A Cochrane review of interventions to prevent weight gain after smoking cessation found that:
- Individualised interventions, very low-energy diets and cognitive behavioural therapy may reduce weight gain associated with smoking cessation, without affecting quit rates
- Additionally, exercise interventions may be effective in the longer term (12 months)
- General advice to avoid weight gain has not been found to be effective and may reduce quit rates
- The health benefits of smoking cessation are broad and are likely to outweigh risks of weight gain (quitting smoking would be priority)
9
Q
Causes of obesity…
A
- complex
- everyone is different
- Separate the disease of obesity from gluttony
- Genetics and the environment
* Obesogenic environment
- Genetics and the environment
- Physiology of weight regulation by hypothalamus
* Body defends its fat- Leptin, orexigenic and anorexigenic neurones
- Physiology of weight regulation by hypothalamus
- everyone lives within a weight range
- aim to keep people at the bottom of their range
10
Q
The disease of obesity…
A
- Lifestyle and habits
- Psychological factors
- Comfort eating
- Psychological illness and obesity
- Ppl with obesity ↑ likely to become depressed
- Ppl with depression are ↑ likely to become obese
- Link with weight gain and antipsychotics
- physical and developmental factors
- Reduced mobility–>less likely to be able to exercise
- Intellectual disability–>increased risk of obesity
- Sociodemographic factors
- Socioeconomic disadvantage–> more likely to be obese
- Rural and remote
- ATSI and CALD backgrounds
11
Q
How do genetics and the environment contribute to obesity?
A
- genetics
- inheritability - one of the strongest predictors of a child’s weight is the weight status of his or her parents
- Early life experiences
- Maternal health and nutrition during pregnancy
- Low birth weight infants
- Accelerated weight gain in early life
- environment= obesogenic
- cheap processed foods- high in fat, sugar, salt, xs kj
- Portion sizes have increased
- Cultural and social aspects of food intake have changed
- Urban design and built environment
- Sedentary jobs, long work hours, both parents working
12
Q
Whats the physiology of weight gain?
A
- Calories in
- Dietary choice and willpower (hormones will try and overpower)
- Calories out
- Exercise (~5-10%)
- Basal metabolic rate
13
Q
Whats the physiology of weight gain?
A
- All components of energy balance, including energy intake and expenditure, interact with each other to affect body weight
- The body attempts to maintain energy balance and protect existing body weight through a complex negative feedback system involving hormones that:
- increase hunger (e.g. ghrelin)
- Inhibit food uptake in the short term (e.g. cholecystokinin, PYY, oxyntomodulin, amylin, GLP1)
- Inhibit food intake in the long term (e.g. leptin and insulin)
- Increase metabolic rate and energy expenditure (e.g. triiodothyronine [T3])
- System defends against weight gain as well as weight loss under normal circumstances but energy balance cannot be maintained when an energy surplus is sufficiently large and sustained (eg ↑ junk food ↓ exercise)
- Weight gain will begin and usually continue until a new weight results in increased energy expenditure and energy balance is re-established
- The same physiological mechanisms then seek to maintain energy balance at the higher weight, and will defend against weight loss by increasing appetite and reducing energy expenditure if there is an energy deficit
- Most overweight and obesity results from upward resetting of the defended level of body weight, rather than the passive accumulation of excess body fat
- Homeostasis – hypothalamus uses orexigenic hormones to change your behaviour to make you eat
14
Q
Whats the role of the microbiome in obesity?
A
- There is tremendous interest in the possibility that highly processed foods, non-nutritive sweeteners, and other artificial additives may impact body weight beyond the calories they contain either directly or indirectly through modification of the gut microbiome
- This is an area of intense research with no definitive results that would change current recommendations
- Germ-free mice – put on weight when given faecal transplant from an obese person but not when given a faecal transplant from a lean person
15
Q
Is being overweight bad for you?
A
- yes??
- Adult obesity is associated with a striking reduction in life expectancy for both men and women
- The steady rise in life expectancy seen during the past two centuries may end because of the increasing prevalence of obesity
- Benefits of exercise
- Unfit individuals have approximately 2x ↑risk of mortality (regardless of BMI)
17
Q
Obesity: a major contributor to disease
A
