Obesity IV

Question 1

Regular physical exercise offers what 7 benefits in treating obesity?

Answer 1

*It may increase weight loss
*It improves, independent of weight loss, glucose tolerance, blood pressure and lipids
*It increases lean body mass
*It likely improves long-term dietary compliance
*It improves mood and may alleviate depression
*Regular exercise is the best predictor of long-term weight loss
*It decreases morbidity in physically fit obese/overweigh

Question 2

What constitutes moderate intensity exercise?

Answer 2

–Strict definition is exercise that raises your heart rate (HR) to 55-69% of your maximal HR
–Maximal HR = 220 – Age
–So for a 20 year old (220-20) x 0.55 (and to 0.69) = target would be 110138 beats/min
–More casual definitions
*Moderate intensity (55-69%) –can hold conversation, but not sing and noticeable increase in HR and breathing rate
*High intensity (70%+) –can only talk in short phrases and HR is substantially increased as with breathing rate
VO2 max = capacity of body to move O2 from lungs to all cells in body

Question 3

Why do 70-75% of adults do not meet even CDC guidelines for exercise and how can we improve on that?

Answer 3

*Both healthy and obese individuals find it difficult to:
*Initiate exercise (motivation, busy, not enough time, too tired, too lazy, too inconvenient)
–The more such reasons reported the more likely it is they will not initiate an exercise program
*Maintain a program of exercise

*Both of these can be ameliorated by *Behaviour therapy
*Lifestyle programs, which attempt to embed physical activity within peoples daily lives
–Intermittent activity
–Pedometer

Question 4

What is the aim of behavioural therapy and how do we achieve it?

Answer 4

*Almost no obesity intervention is now without this component
*The aim is to identify the behavioural factors which promote problem behaviours (e.g., overeating) and prevent uptake of healthy behaviours (e.g., exercise)

*It does this through:
–Identifying appropriate GOALS
–Identifying how to achieve them
*Designing small incremental changes (shaping)

Question 5

What are 4 treatment components of behavioural therapy?

Answer 5

*Self monitoring (detailed diary of food intake, exercise etc)
–Reveal hidden patterns that the person is unaware of
–Confront the person with what they are actually eating (some studies indicate 50% under-reporting in the obese)
–Such self-monitoring correlates with long-term weight control
*Stimulus control (identifying cues to eating)
–Involves simple premise of out of sight out of mind (+ reverse)
»Put food away, serve small portions, no extra food on table, and remove uneaten food ASAP
*Cognitive restructuring (“I’ve blown my diet, so I might as well stuff my face”to “this is just a lapse -not a disaster”)
–Uses role playing to deal with such situations
–Addresses achievable weight loss goals and fear of failure
*Time limited therapy sessions
–Group format superior to individual format

Question 6

What are the short and long term benefits of behavioural therapy?

Answer 6

*Behaviour therapy in association with dieting is significantly better than diet alone in the short term
*More weight is lost (5-10% vs 5%)
*Compliance is better (at around 80%)

*The benefit of behaviour therapy for long term weight loss is not currently known
*People tire of repeated clinic/therapy visits
*Phone/internet/email contact with the therapist may facilitate longer-term maintenance of weight gains -this is disputed by some

Question 7

What is the major advantage of medications for weight loss?

Answer 7

It is far less reliant upon self-control

Question 8

What are the 2 main approaches to medications for weight loss and how is a medication deemed effective?

Answer 8

Centrally and peripherally acting drugs
*To be classed as effective, medication needs to reduce weight by more than 5% (FDA) or 10% (EMA) -relative to placebo
*This is a highly contested issue as approval depends upon a drug meeting the FDA/EMA effectiveness criterion, so there is an incentive to make the placebo control condition as ineffective /as possible
*It is then possible (perhaps even likely) that many approved weight-loss drugs may be no more effective than really well-designed weight loss programs (i.e., diet, behaviour therapy, exercise etc)

Question 9

What is Phentermine? (6)

Answer 9

Centrally acting drug
*Phentermine and its derivative medications have been used for over 50 years and are the most widely prescribed weight loss drugs
*Several clinical trials have established their efficacy (around 5% at 1 year) and they are all well tolerated
*Phentermine exerts its therapeutic effect via the hypothalamus, where it binds to TAAR1 receptors causing synaptic release of various monoamines –the consequence is to reduce hunger
–Phentermine also affects peripheral fat cell metabolism
*Phentermine may now be prescribed with topiramate, which together produce greater weight loss than either alone (around 9% at 1 year)
–Topiramate has a harsher side-effect profile than phentermine (impaired cognitive function, psychomotor slowing, paresthesias)
*Over 1 year, effectiveness plateaus and some weight-regain may occur, this is a common feature of all weight loss drugs

Question 10

What is Orlistat? (6)

Answer 10

Peripherally acting drug
*Orlistat blocks pancreatic lipase resulting in a failure to digest fat
*Around 30% of ingested fat is not digested (excreted)
*The adverse consequences of eating lots of fat whilst taking Orlistat are highly aversive
*Orlistat also produces weight-loss independent improvements in blood lipids
*It is not licensed for long-term use and anyway most people could not tolerate it longer term (with high drop out rates in clinical trials due to its side-effect profile [fecal incontinence & urgency])
*It has a weight loss efficacy less than Phentermine (around 3-5% at 1 year)
*Cetilistat has an improved side-effect profile but there is not as yet an extensive database of clinical trials to determine its efficacy

Question 11

What are 2 restrictive surgical procedures?

Answer 11

–Gastric banding
*In this case the volume of the stomach is reduced to 30cc by staples or banding
*The benefits of this approach depend upon patient compliance (drinks!)
*Effectiveness at 1 year is weight loss of 30-50% of initial body weight
*Low morbidity and reversible
*Side effects: Gastric reflux & vomiting; Solid food intolerance; Stenosis of surgical stoma; Ulcers & hernia

–Vertical sleeve gastrectomy
*Restrictive, irreversible, but with additional benefits (similar to Roux-en-Y)
*Performed laparoscopically
*Effective in children (no growth slowing)

Question 12

What are 3 malabsorptive procedures?

Answer 12

–Shortening of the small intestine (SI)
*Here a varying length of the small intestine is bypassed so that food simply can not be digested. This procedure is now not generally used

–Roux-en-Y gastric bypass (REGB)
*This involves a threefold process
–The stomach is reduced in size
–The new stomach pouch exits into the SI (one arm of the Y)
–The old remnant of the SI from the stomach is connected to the new SI connecting arm forming the other arm of the Y
*The small pouch limits meal size
*The smaller SI length restricts absorption of food
*The food remains longer in the SI before it encounters bile/pancreatic juices from the other arm of the Y
*Dumping syndrome occurs if sugars/fats are eaten to excess
*Rapid benefits to Type 2 Diabetes & alteration in food prefs

–Endobarrier

Question 13

What is the Roux-en-Y gastric bypass outlook? (8)

Answer 13

*At 1 year patients have typically lost 50-60% of their initial body weight
*This is maintained for at least 14 years -but there is a catch
*Such patients need continuous medical supervision
–X-ray contrast 1 day post surgery (leaks)
–Liquid diet for 2 weeks
–Soft solids for 6 weeks
–By 3 months varied diet -but several small meals and water in between to minimise side effects
–6 monthly follow-up for ever, along with dietary supplements and vitamin B12 injections
*This surgical treatment is the ‘gold-standard’ approach, but is rapidly being superseded by the sleeve gastrectomy

Question 14

What are the 3 forms of body dissatisfaction in normal weight people?

Answer 14

*As a distorted body image -“I am fat”
*As a discrepancy from an ideal -“I think I am larger than I would like to be”
*As a generally negative appraisal of ones body -“I don’t like my body”

Question 15

What are 4 methods of measuring perception of body image?

Answer 15

–Projection measures (e.g. adjust spots to represent hip size and compare to actualhip size)
*Most people (especially women) overestimate their size
*This effect is most pronounced in those with an eating disorder
–Computerised morphing measures (self & other)
–Perceived vs ideal body size/shape (see below)
*Which one do you resemble VS which one you would like to look like
–Negative thoughts about the body (questionnaires)

Question 16

Who is dissatisfied? (6)

Answer 16

*Many women (50-75% percent)
–55% with their weight overall
–57% with their stomach
–50% with their legs
–32% with their breasts
*Some men (30%+)
–Tendency to focus on muscularity (especially upper torso)
–Evidence strongly suggest increasing body dissatisfaction
*Body dissatisfaction (BD) appears in females at 8 or 9 and is consistent across the lifespan
*BD is more common in Westernised nations
*BD appears more common in higher SES groups
*BD also increases in migrants as they acculturate

Question 17

Why are people dissatisfied with their body? (2)

Answer 17

*The media (TV, magazines etc)
–Thin women and muscular men are portrayed as ‘the norm’
–Of course, the population at large is not like this and there is considerable evidence that the media is highly non-representative in its portrayal of ‘normality’
–Experimentally, showing men or women such thin or muscular figures increases their body dissatisfaction
*This effect occurs in normal weight, anorexic, bulimic and pregnant women
*Relatedly, seeing images of obese individuals improves body satisfaction
–If these effects occur for such acute exposures, imagine what chronic exposure may do

*The family
–Daughters tend to reflect their mother’s level of body dissatisfaction
–This could result from mothers and daughters sharing similar physiques and so experiencing similar social pressures

Question 18

What is the cause of body dissatisfaction?

Answer 18

The media could simply be responding to what they believe the public desires, but the fact that exposure to such images produces increased body dissatisfaction suggests a causal role

Question 19

What is the psychology of dieting? (5)

Answer 19

*A central concept in this regard is ‘Restrained eating’
*According to researchers in this area, body dissatisfaction leads to dieting, which is seen as a conscious attempt to restrainor exert controlover body size and food intake
–Restraint is typically measured by questionnaire
*Note here the similarity between the Western social ideal of individual autonomy (control over ones destiny) and the notion of control over ones weight
*No wonder then that fatness is equated with a failure of self-control and is thus stigmatised on this basis

Question 20

What famous study was conducted on restrained eating?

Answer 20

–Participants (dieters vs non-dieters) are given either a high calorie preload or a low calorie preload
–Then they are asked to participate in what they are led to believe is another experiment, which involves tasting and rating ice-cream
–They are told to sample as much of the ice-cream as they like as it will all be thrown away after their session is completed
–This is for a set period of time and is unobserved
–The DV (unknown to them) is how much ice-cream they eat
*The non-dieters compensated their intake
*However, dieters showed the reverse pattern
*A high calorie preload led to increased consumption relative to a low calorie preload
–Further experiments using Strooplike tests revealed that these type of manipulations engage cognitions directed against self imposed food restriction -“what the hell!”
*A caveat: The effect is not always replicable, which may relate to measurement of restraint amongst other thing

Question 21

How many people are currently malnourished and where are they?

Answer 21

–World population is 7.6B and roughly 1B are malnourished
*Estimates vary and severe malnourishment may cover -0.5-20% (total pop.)
*Milder forms –up to 50% (total pop.)
*Even in the USA malnourishment may affect 0.5 Million children
*Children may be the most adversely affected (school attendance; biological effect on IQ)
*Asia and Africa have the highest incidence

Question 22

What are the 2 types of malnourishment?

Answer 22

*Malnourishment may be chronic or acute
–Chronic malnourishment in children can cause stunting (defined as height for age is greater than 2 SD below Mean)
–Acute malnourishment in children/adults causes wasting (as does chronic malnourishment in adults)
*Chronic malnourishment is the norm, with exacerbations (acute) under times of famine
*Famine typically does not occur in a vacuum, it usually occurs within the context of on-going societal problems

Question 23

What are 2 theories of famine?

Answer 23

*Theories of how famines come about can be broadly categorised into two
*Those that emphasise human catastrophes
*Genocide, war, preexisting social unrest, unstable social structures, poverty, poor government, poor communications

*Those that emphasise natural catastrophes
*Plagues, tempests, flooding, drought

*Pure examples of either are rare, as both factors generally combine

Question 24

What is the social trajectory of famine? (7)

Answer 24

–The moral economy (i.e., sources of informal support)
–Agrarian workers and landlords/employees
–Relationship to family, neighbour, tribe
–Religion
–Reduced food intake and meal spacing
–Use of wild foods (frogs, rats, seaweed, grass)
–Sale of non-essential possessions (cooking gear)
–Sale of all possessions (farming implements, land) –The PNR
–Migration
*To cities/towns (slum-dwelling) and refugee camps
–High morbidity from unclean water -GI tract infections -aided by reduced immune function from malnourishment

Question 25

How does famine affect people in different ways? (4)

Answer 25

–Children suffer because they require far more protein than adults
–The health of the foetus may be adversely compromised which may have demographic consequences decades later
–Deaths usually first hits the elderly, infants, then adult males
–Women and older children are often the last to die

Question 26

How does famine affect children?

Answer 26

*PEM (Protein/Energy malnourishment)
*PEM has two extremes
*Marasmus (defn: wasting away) results from a diet insufficient in calories (energy)
*Kwashiorkor (defn: ‘the disease a baby gets when a new baby is born’–from the Ivory Coast, W. Africa) results from a diet sufficient in calories, but insufficient in protein
*In a famine children will typically fall on a continuum between these extremes

Question 27

What are the symptoms and treatment/outcomes of marasmus?

Answer 27

*Symptoms
*Extreme underweight for age (60% below the 50th percentile)
*Irritable, crying, apathy
*Wizened, shrunken
*Chronic diarrhea

*Treatment/outcome
*Refeeding and hydration
*Opportunistic infection

Question 28

What are the symptoms, treatment/outcome and long term effects of Kwashiorkor?

Answer 28

*Symptoms
*Edema
*Sores (skin, membranes)

*Treatment/outcome
*Rapidly fatal if untreated
*Milk is best treatment

*Long-term effects of PEM
–These can be partially reversed but the effects are often long lasting

Question 29

What are the long term effects of PEM?

Answer 29

*PEM is associated with long term disadvantage
–50% of PEM sufferers later have an IQ < 90, compared to a similar but non-PEM cohort (17%)
–Apart from IQ, PEM is also associated with attention and STM problems

Question 30

What are the effects of famine on pregnancy? (4)

Answer 30

*Severe malnutrition of the mother results in spontaneous abortion (up to 4 weeks into pregnancy)
*Malnutrition alone definitely:
*Reduces brain weight, and number of neurons and glia
–Not surprising as 250,000 neurons per minute are grown during fetal development
*Has effects that are irreversible by good nutrition later in life
*It has been suggested:
*That raised BP, proneness to Type II diabetes and heart disease may all be consequences of poor maternal nutrition
*Epigenetic basis studied in the Dutch famine cohort (1944)

Question 31

What are the effects of famine on adults? (7)

Answer 31

*Severe malnourishment in adults has a range of physiological effects
–It produces impotence in men and eliminates the menstrual cycle in women
–Loss of lean and fat body mass
–Lowered heart rate, Basal metabolic rate & Blood pressure
*Females may be able to reduce BMR further than men, which may explain their greater ability to survive famine
–Edema
–Lethargy and hypersensitivity to cold
–Severe impairment of immune function
*It is usually the latter which kills, in combination with the unsanitary conditions prevalent in such situations

Question 32

What were the psychological effects of the famine study? (10)

Answer 32

*Baseline period
–All willingly participated and were full and engaged participants for the first part of the study
*Starvation period
–Numerous psychological effects were observed, but no change in IQ or memory measures
*Apathy, depression, tiredness
*Irritability
*Loss of spontaneous activity
*Narrowing of interests
*Loss of libido
*Loss of interest in personal appearance
*Violence in 2 men
*Little interest in carrying out their routine duties
*A major finding (perhaps not surprisingly) was food preoccupation
*Thoughts and talk continuously on food *Recipe and cookbook collecting
*Planning how they would eat the next meal
*All food dislikes disappeared and the monotonous diet of cereals, potatoes and turnips (28g of protein & 22g fat) got to be liked more and more
*Heightened possessiveness about food
*Meals could last up to 2 hours
*Extreme reactions if anyone wasted food
*Extensive gum chewing, nail biting and smoking
–The tone became somber, serious and the humour sarcastic
–All participants became highly ego-centric
–Social interaction became stilted and artificial
–The men became unable to control outbursts of temper etc, even though they were aware of their irritability
–Table manners were totally abandoned
–Attitudes were expressed at total odds with those reported early in the study (ego-centric)
*After 3 months of refeeding most of the psychological effects had dissipated, but further studies with other populations suggest that the psychological effects of starvation are lifelong

Question 33

What do Holocaust survivors report on their psychology of food? (6)

Answer 33

*Extreme reactions to throwing out food
*These also occur even when food is spoiled
*Storing excess food (e.g., putting bread in bedside drawers)
*Difficulty standing in line for food
*Anxiety if food is not available in the immediate vicinity
*Craving for carbohydrates

Question 34

What are the effects of food deprivation on longevity? (6)

Answer 34

• Nearly 80 years of experimental research using various animal models has suggested that some form of dietary restriction may significantly increase lifespan
  *In 1934 McCay and Crowell demonstrated that rats fed a reduced caloric diet lived twice as long as control rats
  *These findings have been replicated many times in a diverse range of animals from fruit flies to mammals
  *Maintaining a youthful appearance
  *Higher activity levels
  *Delays in developing age-related diseases
  *However, semi-starvation diets do not result in extended lifespan in Rhesus monkeys (the closest test yet to trying this in humans)
  *Semi-starvation diets are difficult to test in humans
  *Infants can not be assigned to either a calorie restricted treatment group or a normal control group
  *Nonetheless a study started with older participants in 2002 indicates benefits for reduced BP
  *Some suggest this study is flawed as the effects of caloric restriction may only work when the animal/person is young

Question 35

Why might food deprivation lengthen life-span?

Answer 35

*Hormesis (‘excitation’) hypothesis
*Low intensity biological stress may put the organism into a ‘defensive state’ which slows metabolism and ageing
*Perhaps such a state could be initiated without using a starvation diet by promoting physiological factors that generate leanness?

*Free radicals
*Mitochondria generate more free radicals when energy is abundant
*According to this theory it is free radicals which promote cell ageing
*Cutting calories cuts free radicals, thus slowing ageing

*Currently, how food deprivation extends life span is not understood –and similarly, we do not really know whether it will occur in humans