Runaway Weight Gain Train
Now we have an understanding of how obesity is classified and an idea of the statistics of how obesity is becoming a global epidemic, we are going to look at the causes of obesity.
According to (Swinburn & Egger, 2004) there are a number of vicious cycles that act as accelerators that either maintain or increase peoples weight. (Swinburn & Egger, 2004) liken this to a ‘runaway weight gain train’ that is travelling down a steep downhill slope of obesogenic environments. The ‘runaway weight gain train’ does have a break but is not strong enough to slow the train, as it is weak in comparison to the vicious cycles. The diagram below shows the idea of the ‘runaway weight train gain’.
The obseogenic environment according to the Foresight Report (Butland, 2007b)refers to the role environmental factors may play in determining both energy intake and energy out. It has been defined in the foresight report (Butland, 2007b)as the sum of the influences that the surroundings, opportunities or conditions of life have on promoting obesity in individuals and populations.
According to (Bean, 2006)your daily calorie needs, energy in, will depend on your genetic make up, age, weight, body composition and daily activity. In obese individuals the energy in (food) will be greater than the energy out resulting in weight gain. (Holford, 2005)stated that although most people believe eating too many calories causes weight gain, the average calorie intake in Britain has dropped in the last 15 years. Yet from the statistics stated by(Statistics on obesity, physical activity and diet : England 2006, 2007), we know obesity has increased. (Holford, 2005)believes different activity levels would explain this.
As in the ‘Runaway Weight Train Gain’ model the first wheel of the vicious cycle is movement inertia: (Swinburn & Egger, 2004)state that although obese people expend more energy whilst performing a task than their lighter counterparts, the obese individual tend to do fewer of those energy demanding tasks. (Ferraro, Boyce, Swinburn, De Gregorio, & Ravussin, 1991)agree with Swinburn and Egger with their research showing that heavier individuals are less active and expend less energy in physical activity than lighter individuals. According to (Pietiläinen et al., 2008)physical inactivity in adolescence strongly and independently predicts abdominal obesity in young adulthood. Thich continues the vicious cycle of the obesogenic environment.
The next wheel on the ‘Runaway Weight Train’ model is linked with the movement inertia wheel, which is mechanical dysfunction. (Swinburn & Egger, 2004)suggest mechanical dysfunction would restrict movement, cause difficulty in walking, cause pain, shortness of breath, fatigue and anything else that would further limit physical activity and increase weight again. This would directly link with the movement inertia cycle because if you have limited movement as a result of fatigue or pain due to being obese, you are then less likely to move around. A study by (Han, Tijhuis, Lean, & Seidell, 1998)indicates that participants in their study on quality of life, that subjects with large waist circumferences or high BMI were more likely to have poor physical functions that limited their movements for basic activities such as walking, bending, carrying shopping and going up stairs. The study goes further than physical functions, but also includes psychosocial health as one of the dimensions looked at as part of quality of life, which leads us onto the next wheel on the ‘Runaway Weight Train’ model: is physiological dysfunction.
(Swinburn & Egger, 2004)stated that psychological dysfunction of obese individuals come from body dissatisfaction, physical discomfort and social stigma, which would trigger depression, anxiety and feelings of low self-esteem. The study by (Han et al., 1998)indicates that obese men and women would rate their own psychosocial health (that is self-esteem, mood and positivity) as poorer than the non overweight men and women. These psychological dysfunctions would add to the obesogenic environment and it is suggested by (Swinburn & Egger, 2004)that the consequence would be binge eating, comfort eating, excess alcohol intake or reduced physical activity. We can see here the vicious cycle because if an obese individual binge or comfort eats, it could result in periods of depression poor mental and physical energy causing the cycle to start again according to (Holford, 2005)
The next wheel of the runaway weight gain train (Swinburn & Egger, 2004)is the diet cycle. This cycle is the idea that the old and new diets that are unsustainable for the majority of the population, cause the participant to fail and may contribute to the psychological problems in the previous cycle. Diet is linked with the modern obesogenic environment we live in; The Foresight Report (Butland, 2007a)suggests there is a surplus of energy-dense, low-cost, nutrient deficient food that will contribute to weight gain. According to (Holford, 2005)a diet mad up of the wrong kinds of food, or lacking in nutrients can cause bloating, inflammation and gut infections (which can affect the brain, nervous system, hormonal balance and the ability to detoxify). The Foresight Report (Butland, 2007a)identifies that the hormonal balance and neural pathways control how adipose tissue and muscles use nutrients for muscle, if these hormones are out of balance the feedback loops could be broken and contribute to weight gain.
(Romaniello & Bornstein, 2013)talk about hormones being important, as they will change things from the inside out. It is important to understand the roles of different hormones in the body, what they do, and how they affect you mentally, physically and emotionally, these all relate to the other wheels of the ‘runaway weight gain train’ (Swinburn & Egger, 2004). The hormone testosterone, according to (Romaniello & Bornstein, 2013), is one of the most important hormones as it is part of your genetics and it is the driving force of your health, however it is stated that the average level of testosterone has dropped around 20-30%. The drop in testosterone would contribute to the increase in adipose tissue due to the hormone testosterone being one of the main hormones for building muscle and reducing adipose tissue.
The opposing hormone to testosterone is estrogen. This is due to it being on a sliding scale, if one goes up the other goes down and visa versa. (Romaniello & Bornstein, 2013)describes estrogen as one of the more interesting hormones due to the fact that it is an essential hormone, however too much will have a potential downside. (Learney, 2014)confirms that as estrogen dominance increases so does adipose tissue. Ii is suggested in order to keep estrogen levels down we limit stress, also know as cortisol.
The stress hormone, cortisol, is a hormone that can be effective for weight loss, but too much will cause weight gain. According to (Romaniello & Bornstein, 2013)cortisol is linked with the fight or flight mode, which when doing physical activity can be useful for increasing performance and increasing the energy used. However, if cortisol remains elevated for long periods of time, it will increase insulin levels, which can cause you to crave more sugar dense foods.
Insulin, according to (Learney, 2014), is a hormone secreted after we eat food or to regulate blood glucose levels. (Romaniello & Bornstein, 2013)goes on to state that insulin is responsible for the uptake into cells in your liver, muscles and adipose tissue. It is believed we are becoming more insulin resistant due to eating higher sugar based foods, which cause our insulin levels to be constantly spiked. When we become insulin resistant, our blood sugar levels stay higher for longer periods of time because the transportation pathway gets slowed down causing the body to become less efficient delivering nutrients to their desired stores. When this happens, the glycogen doesn’t make it to the muscles to be used as fuel but instead get stored as adipose tissue. According to (Learney, 2014), as an individual increases in weight the degree of insulin resistance will rise.
(Romaniello & Bornstein, 2013)suggests the second most important hormone is the growth hormone. Testosterone and growth hormone work best in conjunction with one another. Individually they are both important hormones but when combined the impact is more beneficial. It has been suggested that higher levels of growth hormone improve the amount of lean tissue you have, protect your immune system, help fight off disease and help you to stay healthy. Growth hormone is lined more with the movement inertia and dietary food timing than just diet itself.
The last two hormones to look at are leptin and ghrelin. Leptin is important according to (Learney, 2014)as it is an anorexigenic hormone that controls energy intake and energy expenditure which is the fine balance of maintaining a healthy weight or becoming under or over weight. Anorexigenic hormones cause the loss of appetite, where as orexigenic hormones increase appetite. (Learney, 2014)continues on to state that obesity is not brought about due to poor nutritional choices and lack of will power but due to compounding genetic and environmental factors. It has been suggested that leptin is correlated to the set point theory whereby according to (Weinsier et al., 2000)the body has a homeostatic feedback system for controlling adipose tissue. The homeostatic feedback system include a mechanism to make us more or less wasteful in our energy expenditure, meaning we could down-regulate our resting metabolic rate and burn less energy to regain weight lost. (Learney, 2014)confirms this by stating that once an individual loses adipose tissue, the level of leptin correspondently goes down as well. (Romaniello & Bornstein, 2013)states leptin influences other hormones that regulate the metabolism, such as the thyroid hormones T3 and T4. When leptin levels are high so too are the production of T3 and T4, allowing us to reduce adipose tissue. When leptin levels are low, so too are the thyroid hormones. Ghrelin, also known as the hunger hormone, share the same brain cells as leptin according to (Learney, 2014). Ghrelin is a fast acting hormone that appears to play a role in initiating eating. According to (Romaniello & Bornstein, 2013), ghrelin not only initiates hunger but is also secreted by it, meaning when your stomach starts producing ghrelin we start to feel hungry and when we are hungry ghrelin is secreted. (Learney, 2014)states ghrelin is inversely related to bodyweight, ghrelin levels will increase to make you hungry when weight loss is initiated.
When looking at (Swinburn & Egger, 2004)‘runaway weight gain train’ model we can see how hormones would fit into the dieting cycle as the diet we choose to follow will have a direct impact on our hormones, which in turn has an impact on how we process and store the energy.
The last wheel of the ‘runaway weight gain train’ (Swinburn & Egger, 2004)is the low socioeconomic status cycle. It is suggested that in developed countries your socioeconomic status is strongly associated with obesity. This relationship seems to cross over to obesity reducing job opportunities, lowering education, and social exclusion. (R. Puhl & Brownell, 2001)argues that there aren’t any systematic reviews of scientific evidence that overweight individuals receive poor grades, have less job opportunities and that it is mainly storytelling. (R. Puhl & Brownell, 2001)does suggest there is evidence that obese employees may have a lower wage to their average weight counterparts. Stereotypes such as overweight employees being lazy, having a lack of discipline, being less competent, having a poor attendance, and being poor role model are some of the reasons for the wage penalty of obese employees. From statistics a more recent article (R. M. Puhl & King, 2013)it shows obese women earn 6% less than healthy weight women, and obese men earn 3% less than their non-obese counterpart. It has been estimated that for women, every one-unit point increase on the Body Mass Index score is associated with a 1.83% drop in hourly wage. It is reported by (R. M. Puhl & King, 2013)that this trend has been documented across all race and gender groups with the exception of African American men and women.
(Swinburn & Egger, 2004)suggests a lower wage would reduce the range of healthy food choices that would be available, which links with the diet cycle, and less recreational activities would be available, which links to the movement inertia and mechanical dysfunction cycles. The idea of poor quality food and less exercise would contribute to the obesegenic environment.
The low socioeconomic status in relation to education would also increase the weight gain cycle. According to (R. M. Puhl & King, 2013)obese students encounter negative stereotypes with the perception that they have poorer social, reasoning, physical and cooperation skills than non-overweight students. These negative stereotypes may limit the educational opportunities for obese students and have an impact on their future jobs and wages, which creates a vicious cycle for that student and their future family. According to (R. M. Puhl & King, 2013)there is a relationship between poor school performance and body weight index. There are still more studies needed to be done into this to see to what extent weight stigma contributes to the educational outcomes.
Low socioeconomic status according to (Swinburn & Egger, 2004)is associated with higher cortisol levels, which as (Romaniello & Bornstein, 2013)mentioned the higher your cortisol levels the more adipose tissue you will hold, causing comfort eating which results in even more weight gain and continuing the ‘runaway weight gain train’.