Obesity

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= OBESITY & OVEREATING: = 1. Discuss Factors Related to Overeating and the development of Obesity

Biological - Musuclo-skeletal problems - Cardiovascular disease - Some cancers Obesity is associated with increased risks of the following cancer types, and possibly others as well: - Sleep apnoea - Type 2 diabetes - Hypertension
 * Genetic predisposition can influence the amount and rate at which weight is gained and lost
 * Certain medical conditions, for example hypothyroidism are known causes of overweight
 * Energy expenditure (metabolism, thermogenesis and physical activity)
 * Health Consequences of overweight and obesity
 * Esophagus
 * Pancreas
 * Colon and rectum
 * Breast (after menopause)
 * Endometrium (lining of the uterus)
 * Kidney
 * Thyroid
 * Gallbladder

- According to Phillipe Froguel, the GAD2 may be responsible for obesity for about 1 in 10 seriously overweight people - Imperial study of more than 1200 people identified 2 forms of the GAD2 gene - One protected against the obesity, the other made it more likely by stimulating appetite - Thinner volunteers were found to be more likely to carry the protective form of the gene while the other version was more common in obese people - Stimulates overeating by speeding up production of GABA (gamma-aminobutyric acid) - GABA is an amino acid which acts as a neurotransmitter in the central nervous system that is responsible for hunger.
 * **The Gene GAD2 **

- Body size runs in families - Stunkard et al. (1990) studied 93 pairs of identical twins who were reared apart - Compared twins’ BMI and found that genetic factors accounted for 66%- 70% of the variance in their body weight - Concluded that there must be a strong genetic component in the development of obesity, but also that genetics played a greater role in those twins who were slim - Although results from twin studies indicate a genetic factor in obesity, the role of the factor is not clear
 * ** Genetic Predisposition **
 * Energy imbalance – when the number of calories consumed is not equal to the number of calories used


 * Genetic Theories **

Family -Obesity often runs in the family. If one parent is obese, there is a 40% chance of their child being obese. If both parents are obese, this raises to 80%. -The probability of thin parents producing obese children is only 7% -However it is still unclear how genes are involved in obesity and to what extent.

Twin studies -MZ twins reared separately are more similar in weight than DZ twins reared together. - ** Stunkard et al. (1990) ** examined the BMI of 93 pairs of MZ twins reared apart and found that genetic factors accounted for 66-70% of variance in body weight. However, the role of genetics seems stronger in lighter twin pairs than heavier ones. Appetite regulation -Appetite control may depend on a genetic predisposition -A gene connected with profound obesity in small animals has been identified, however this is still unclear for humans. - ** Leptin ** deficiency was first described in 1997 (by Montague et al.) in two cousins with severe early-onset obesity who had no detectable serum leptin. These subjects are the human equivalent of the ob/ob mouse. The children were from consanguineous unions, had food-seeking behaviours that were non-distractable, and were of normal intelligence. Treatment with recombinant leptin resulted in weight loss and normalisation of eating behaviour (Farooqi et al. 1999).
 * Montague et al. (1997) **

- ** Tataranni et al (2003) study on Pima Indians ** “Tataranni et al. (2003) measured the body weight gain in 92 free-living Prima Indians to evaluate the effect of energy intake vs. expenditure. Prima Indians living in Southwestern Arizona are one of the most obese populations in the world. Changes in body weight after a follow-up period were available in 74 participants. Tataranni et al. found that a high energy intake is a risk factor for obesity in humans. They also confirmed that a low resting metabolic rate is a risk factor for weight gain in the Prima population.”
 * Metabolic rate theory **

- Maintains the body’s set point weight. Our bodies adjust not only food intake and energy output but also the metabolic rate
===- Ancel et al. (1950), participants went through a semi starvation for a period of 24 weeks. Research had stabilized that the participants were ¾ their normal weight- while eating half of what they previously did. This study was done in the 1930’s in Minnesota.=== === - One of the most important advancements in the understanding of eating disorders is the recognition that severe and prolonged dietary restriction can lead to serious physical and psychological complications (Garner, 1997). Many of the symptoms once thought to be primary features of anorexia nervosa are actually symptoms of starvation. Given what we know about the biology of weight regulation, what is the impact of weight suppression on the individual? This is particularly relevant for those with anorexia nervosa, but is also important for people with eating disorders who have lost significant amounts of body weight. Perhaps the most powerful illustration of the effects of restrictive dieting and weight loss on behavior is an experimental study conducted almost 50 years ago and published in 1950 by Ancel Keys and his colleagues at the University of Minnesota (Keys et al., 1950). The experiment involved carefully studying 36 young, healthy, psychologically normal men while restricting their caloric intake for 6 months. More than 100 men volunteered for the study as an alternative to military service; the 36 selected had the highest levels of physical and psychological health, as well as the most commitment to the objectives of the experiment. What makes the "starvation study" (as it is commonly known) so important is that many of the experiences observed in the volunteers are the same as those experienced by patients with eating disorders. This section of this chapter is a summary of the changes observed in the Minnesota study. === === - During the first 3 months of the semistarvation experiment, the volunteers ate normally while their behavior, personality, and eating patterns were studied in detail. During the next 6 months, the men were restricted to approximately half of their former food intake and lost, on average, approximately 25% of their former weight. Although this was described as a study of "semistarvation," it is important to keep in mind that cutting the men's rations to half of their former intake is precisely the level of caloric deficit used to define "conservative" treatments for obesity (Stunkard, 1993). The 6 months of weight loss were followed by 3 months of rehabilitation, during which the men were gradually refed. A subgroup was followed for almost 9 months after the re-feeding began. Most of the results were reported for only 32 men, since 4 men were withdrawn either during or at the end of the semistarvation phase. Although the individual responses to weight loss varied considerably, the men experienced dramatic physical, psychological, and social changes. In most cases, these changes persisted during the rehabilitation or re-nourishment phase. ===

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- Levine et al., (1999), did a reverse experiment in which volunteers were overfed 1000 calories a day for 8 weeks, some gained an average of 9 lbs. When others gained 1lb- those who gained the least weight tended to spend the caloric energy fidgeting more.===== - When we look at human beings we see all sorts of shapes and sizes. Some individuals are lean, and some carry too much body fat. For lean individuals, body fat is stored enough to last maybe 2-3 months tops, where as obese individuals can carry enough energy to last over a year in length (Levine, 2004). - The variables which determine whether an individual is lean or obese are almost too many to count. For example, a bodybuilder can take in more energy than he or she consumes and still stay relatively lean simply because the excess nutrients are. NEAT 2 directed towards muscle tissue rather than purely to fat. For sedentary individual however most excess energy is stored as fat. - The variable of where nutrients go falls under the umbrella of nutrient partitioning. This is affected by both our diet and exercise. - The second variable is definitely energy balance. In general if energy consumed exceeds energy expended then we gain weight. Because not all energy is partitioned to muscle stores this energy is also stored as fat - Conversely when cutting the goal is to create a caloric deficit, where calories expended exceed calories consumed. - Energy expended can be divided into basal metabolic rate, the thermic effect of food, and activity thermogenesis (Levine et al., 2006). Basal metabolic rate is the energy you expel while at rest, and averages out to be about 60 % of total energy expelled in a given day. - Studies show that the difference between individuals basal metabolic rates (e.g. what makes one person expend more calories than another) is explained mainly by differences in lean body mass (Levin, 2004). This is one of the reasons why when you are dieting your best bet is to do everything you can to maintain the lean body mass you gained while bulking, if not gain additional lean body mass. - The formula is simple 􀃆when calories go down, anticatabolic agents should go up! This includes being extremely cautious about obtaining proper leucine intake (see this months article on leucine practical applications), HMB, fish oil pills, glutamine, high protein intakes, proper pre bed meals, and the consumption of some source of protein in the middle of the night. - The thermic effect of food accounts for 10-15 percent of calories expended in a given day. Essentially eating, digesting, processing and assimilating food requires energy. What is interesting is to study how to manipulate this variable, but that is a topic for another article. Proteins have a greater thermic effect than other macronutrients, followed by carbohydrates, and then fats, which have very little thermic effect. Just by upping the proportion of protein in your diet you can metabolize more fat. - The final category was activity thermogenesis. According to Levine and colleagues this can be further divided into activity associated with exercise and the calories it expends and non exercise induced activity or NEAT. NEAT concerns activities which are physical but fall outside of exercise such as pacing, fiddling, typing, talking, standing, tying your shoes, and other occupational activities performed at work or school Studies indicate that NEAT may explain the majority of the difference between individuals in terms of their energy expended in a given day. In fact, it ranges from 15-50 % of total calories expended in a given day depending on whether an individual is sedentary or active (Levin, 2004, Levin et al., 2006). For individuals who do not exercise this is critical. You will note however that exercise induced energy expenditure is manipulated typically through increased cardiovascular output. - Energy Availability As the primary regulator of NEAT. NEAT is directly correlated with energy intake. As energy intake increases, NEAT levels increase. Evidence even suggests that it is the proficiency of this process which determines whether or not individuals gain excess fat in response to overeating or not. - For example Levine et al. in 1999 overfed a group of individuals, and found that fat gain was inversely proportional to increasing levels of NEAT. In fact, these scientists correlated changes in basal metabolic rate, changes in post feeding thermogenesis and changes in NEAT with fat gain. No significant correlations were found with the other measures. Again, this may be both genetic and environmental. - What is known is that obese rats do not increase NEAT to the extent that lean individuals do in response to overfeeding. Another interesting finding is that during weight loss, much of the decrease in metabolism seen can be attributed to NEAT. - For example, an individual who weighs more will expend more energy when walking or ambulating (pacing). - In a fascinating experiment Drs Weigle and Brunzell took individuals who had lost weight and added weighted vests to them. They found that 50 % of the loss in energy expenditure was made up when the vest was put on. Perhaps along with calorie cycling during dieting you might try a weighted vest, imagine how great it would be if your metabolism did not lower or you didn’t hit the dreaded plateau! - Further, it appears that as energy intake goes down, NEAT goes down as well. So, the current working theory is that as excess energy comes in, the human body regulates it with increased NEAT, or correspondingly decreased NEAT as energy intake decreases such as occurs during dieting.


 * Cognitive **

Research suggests obese individuals often perform poorly in reasoning and planning tasks and, likewise, those with poor cognitive function are more vulnerable to excessive weight gain. For obese people, there was a likely "vicious cycle" relationship between cognition and obesity, with low performance in planning, reasoning and problem solving exacerbating weight gain, which in turn compounds negative influence on the brain via biological mechanisms.

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Research conducted by the National Centre for Farmer Health between 2004 and 2009 reveals that there is a correlation between obesity and psychological distress among the farming community where suicide rates are recognised as high. Chronic stress overstimulates the regulation of the hypothalamic-pituitary-adrenal (HPA) axis that is associated with abdominal obesity. Increasing physical activity may block negative thoughts, increase social contact, positively influence brain chemistry and improve both physical and mental health.

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Psychological factors have also been shown to impact on various aspects of health - including obesity. For example, stress can have a negative impact on lifestyle and is likely to make an indirect contribution to obesity. When people are stressed their food and alcohol intake often increases. There may also be underlying personal issues that, when not dealt with, may lead to a lack of energy or motivation and an increase in food consumption is often seen by an individual as one way of dealing with (or avoiding) the problem. Furthermore, the consequences associated with obesity can in themselves lead to a range of mental health issues - depression, anxiety and low self-esteem all exacerbate the problem (and the result is a vicious circle).

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<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Psychosocial effects on children and adolescents who are obese have been demonstrated, and obese children and adolescents are subject to negative stereotyping and stigmatisation from their peers (Lobstein, Baur & Uauy, 2004). Notwithstanding the effects of chronic disease which can which dramatically effect quality of life, overweight women have been found to be 'less pleased with life' when compared to normal weight women (AIHW, 2001), and some relationships between obesity and depression and anxiety have been reported (Scott et al., 2008).

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Internal-external hypothesis in cog factors of obesity

One cognitive factor that may influence overeating is the internal-external hypothesis. This states that some people ignore internal cues (i.e., hunger), and pay attention to external cues (i.e., taste, smell, variety). These people may eat despite being full, comes back to self-control.

Limitations: -people of normal weight are not particularly good at interpreting internal signals for hunger as well. Hard to measure.


 * Rodin (1984) studied this theory.**


 * Aim:** To find the effect of being external/internal on hunger levels.


 * Procedure:** Rodin made his subjects go 18 hours without food and had blood samples taken. While the blood samples were taken he had a juicy steak wheeled in. He


 * Findings**: Rodin found that the sight increased blood insulin levels and hunger levels in all the patients however the “externals” had the greatest increase.


 * Conclusion:** This experiment shows the connection between psychological state and a biological reaction leading to overeating. It also demonstrates the difference between how external or internal factors influence hunger


 * Criticisms:**Some limitations are that participant factors (size of last meal, metabolism, amount of fidgeting, like/dislike of steak) would have influenced how hungry the participants were and so influenced their insulin levels. Also it is very unethical to starve people for 18 hours.

//<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Source: Inquiry into Obesity in Australia, May 2008 //
 * Socio-cultural factors related to overeating and the development of obesity **
 * **Life events**. Certain life events – such as marriage, giving up sport, and quitting smoking – can cause weight gain. Weight gain after quitting smoking can be significant (i.e. 5 kg in the first year). For this reason, instituting a weight management plan at the time of quitting may help reduce the weight gain that normally occurs after quitting.
 * **Family, work and social environments**. Can influence weight gain and the inability to lose weight.
 * **Diet**. The choices of what food we intake affects weight. The 1995 National Nutrition Survey indicates that:
 * more than 90% of Australians consume foods from the 'cereal and grains' and 'milk product' food groups;
 * over half the males aged 12-44 years and approximately one-third of children aged 4-11 years had not eaten fruit on the day before the interview;
 * total fat (including saturated, monounsaturated and polyunsaturated) accounts for about 33% of the total energy intake of Australian adults;
 * saturated fat accounts for around 13% of total energy intake of Australian adults;
 * no national data exists on salt consumption - however, one study in Hobart indicates only 6% of men and 36% of women are below the recommend maximum 100 mmol/day.
 * **Previous weight loss experience.** If dieting has failed previously, people aren’t as likely to try again, which can cause them to continue overeating and gain more weight.
 * **Physical inactivity.**If we intake more energy than our energy expenditure, the remaining energy is stored as fat, and we gain weight.
 * The National Physical Activity Survey reports against the levels of leisure-time physical activity recommended to achieve health benefits (called sufficient physical activity here). Sufficient activity to obtain a health benefit is defined as the accrual of at least 150 minutes (two and a half hours) of at least moderate-intensity physical activity over at least five sessions in the week before interview.
 * Data from the 2000 National Physical Activity Survey showed:
 * Over 7 million Australians aged 18-75 years (54%) did not undertake sufficient physical activity to obtain a health benefit. Over 2 million of these (15% of people aged 18-75 years) were sedentary, that is they did no physical activity in their leisure-time.
 * Overall, men and women were equally likely to participate at sufficient levels of activity for health benefits (46% and 45%). Younger people were more likely to undertake sufficient physical activity.
 * ** Longer working hours. ** Nowadays, longer working hours mean that people choose food based on convenience. However, these are usually poorer in nutritional values and higher in energy and fat, so this can result in weight gain.

This is a massive book about obesity by the WHO on the internet - [] This is the section about development of obesity – [] Chapter 4 is environmental and societal factors, but there are other chapters about biological and cognitive factors as well ;) lol
 * TELEVISION AND MEDIA **

- To help understand the general ideas behind television and obesity, this is the conclusion of an American essay about the influence of television and media advertising on obesity // Television is a medium that could be used as a powerful educational tool to inform children of good health and nutrition. Instead, it is used as a vehicle for unhealthy persuasion (Galst, 1980). Other countries have used government policy to force marketers to stop promoting (at least directly) unhealthy food to children. The United States is less likely to interfere with the profitability of major corporations and seems unwilling to take more dramatic steps. Yet, it is the United States that faces a potential health crisis, in part created by unhealthy eating. Such a public health crisis has tremendous costs of its own. //

// The link between advertising and unhealthy eating is well documented. In one way or //// another, either through law or public pressure, something must be done to limit the negative //// influence that marketers are having on children’s tastes. It is easy to say that parents simply have to exercise more control over what their children eat, but parents are under tremendous pressure and cannot hope to limit their children’s access to media. If promotion to children is going to occur, and it appears inevitable, more healthy foods must be promoted, and children must eat healthier. In addition, this country must address an obesity epidemic. Only then can the United States look toward a healthier future. //

The full essay is here - []

- This is the abstract of the Galst (1980) study relating to the influence of television on children’s diet



More money is spent on advertising high energy foods than nutritional foods. Children who watch more TV tend to ask for and eat more of these foods, and this in combination with not being as active because of watching TV, they are more often overweight.
 * Watching television. **
 * A study by Salmon, Campbell and Crawford (2006): “Television viewing habits associated with obesity risk factors: a survey of Melbourne schoolchildren”
 * Aim: To examine whether children's television viewing may be a useful indicator of risk of obesity-promoting versus healthy eating behaviours, low-level physical activity (PA) and overweight or obesity among children of primary school entry and exit ages.
 * 1560 children (613 aged 5-6 years [50% boys], and 947 aged 10-12 years [46% boys]) from 24 primary schools in Melbourne, Australia, randomly selected proportionate to school size between 1 November 2002 and 30 December 2003.
 * Information gained through: Parents' reports of the time their child spends watching television, their participation in organised physical activities (PA), and their food intake; each child's measured height and weight and their PA levels as assessed by accelerometry for one week.
 * Results: After adjusting for the age and sex of child, the parents' level of education, clustering by school, and all other health behaviour variables, children who watched television for > 2 h/day were significantly more likely than children who watched television for < or = 2 h/day to: to have one or more serves/day of high energy drinks (adjusted odds ratio [AOR], 2.31; 95% CI, 1.61-3.32), and to have one or more serves/day of savoury snacks (AOR, 1.50; 95% CI, 1.04-2.17). They were also less likely to have two or more serves/day of fruit (AOR, 0.58; 95% CI, 0.46-0.74), or to participate in any organised PA (AOR, 0.52; 95% CI, 0.34-0.80).
 * Conclusions: Health practitioners in the primary care setting may find that asking whether a child watches television for more than 2 hours daily can be a useful indicator of a child's risk of poor diet and low physical activity level.


 * Cultural Influence on Food Preference **



// Abstract of a study – Birch (1991) //

// “This review discusses the development of the controls of food intake during the early years and emphasizes the possible role of early experience in developing eating disorders and obesity. Infants are probably the only depletion-driven human eaters. By the end of the preschool period, eating occurs as a result of a complex interaction of social, cultural, and environmental factors with physiological cues. Children are introduced to the diet of their culture, acquire food preferences and aversions, and learn rules of cuisine, such as when to eat, and even how much to eat. Learning, especially associative conditioning to the social contexts and the physiological consequences of eating, makes major contributions to the formation of food-acceptance patterns during early childhood. //


 * Modernization and Obesity **



<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">
 * Socio-cultural Factors: **

2. Prevention Strategies and Treatments for Overeating and Obesity <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif; font-size: 110%;">Prevention strategies for obesity involve national programs that help to promote healthy diets and physical activity. The 'Global Strategy on Diet, Physical Activity and Health' (DPSA 2004) was formulated by the World Health Organisation to raise awareness of obesity and help those suffering with being overweight. One of the fundamental prevention strategies for obesity is encouraging a balanced diet including a balanced intake of macronutrients (fats, carbohydrates, proteins) and other nutrients (vitamins and minerals). Models for healthy eating, such as the 'Healthy eating pyramid' and the 'Eatwell plate' proposed by the British Nutrition Foundation (2007) advocate healthy eating by suggesting the recommended proportions, quantities and types of food that people should eat.

Targeted children aged 9-13, to be physically active every day. Huhman et al. 2005 conducted a large-scale survey of children and parents to investigate the campaign's effectiveness to create awareness and promote physical activity Findings were that after one year there was an increase in sessions of free-time physical activity. Researchers concluded that commercial advertising in health promotion is promising.
 * VERB campaign - 2002 -2006 in the US. "It's what you do" text page 256 **

Conducted a survey on the efficiency of health campaigns in relation to food habits in Denmark. Found that Health campaigns are useful, however, they cannot stand alone and some have criticised them for being ineffective since they cannot make people change their habits. According to Holm (2002), obesity prevention must address three levels: what the individual can do, what can be done in the community and what should be done by the government.
 * Holm 2002 **

Health education programs raise awareness in the public about health risks and encourage changes in behaviour. For example, media campaigns of the health risks of obesity. Public health campaigns also aim to change beliefs, attitudes and motivations towards overeating and obesity. Another prevention strategy involves changing the wider determinants of health. For example, changing the physical environment (more stairs and fewer escalators) can help individuals undergo more physical activity. Also, creating more exercise facilities, gyms and areas for exercise can encourage physical activity. Private or public health services that can help people change their behaviour (for example, doctors, pharmacies). Political activities are another prevention strategy. For example, legislation aimed at improving and increasing physical activity and set standards for foods available in schools. Also, reducing tax on healthy food and raising tax on sugar and fat filled foods.