Obesity

R Y A N H O L R O Y D

H H P 6 3 7

Obesity: A Multi-Factorial Condition

What is Overweight and Obesity

• Overweight and obesity are defined as abnormal or excessive fat accumulation that may

impair health.

• The First Law of Thermodynamics states that energy is conserved, implying a human body

that takes in more calories (a measure of energy) than it expends in support of bodily

functions must store the additional calories

• Body mass index (BMI) is a simple index of weight-for-height that is commonly used to

classify overweight and obesity in adults. (1)

The WHO definition is:

a BMI greater than or equal to 25 is overweight

a BMI greater than or equal to 30 is obesity.

http://www.extreme-fitness-now.com/

A Cautionary tale to BMI measurement!

Genetics vs Environment?

• The cause of obesity is complex and multifactorial.

• The rapid increase in the prevalence of obesity over the past 20 years is a result of

environmental and cultural influences. (2)

• Over nutrition and sedentary lifestyle have supplanted physical labour and regular

physical activity.

• Genetics play a role, but unlikely to be the case in the United States and United

Kingdoms. (3)

How has the Environment influenced Obesity?

• “There is an urgent need to push back against the environmental forces that are producing.”

(5)

• Factors include:

• Built environment, i.e. layout of streets. (6)

• Increased consumption of sugar-sweetened beverages. (7)

• Exposure to advertising that encourages food consumption and promotes unhealthy

foods. (8)

• Limited time or promotion for daily physical education. (9)

Pedestrian Friendly?• Residing in highly walkable neighborhoods was associated with a lower prevalence of obesity

compared to individuals living in poorly walkable neighborhoods.

• Land-use mix, nearby destinations, and the presence of sidewalks have been associated

• with less obesity. (10)

• Baton Rouge for example is promoting a Walkable, “20 minute” neighborhood. (11)

• But what other factors and measure of accessibility of environment

are available?

http://rainiervalleypost.com/local-group-training-walking-ambassadors-to-lead-rainier-valley-tours/

Walkability

http://www.walkscore.com/LA/Lake_Charles

• Cities are graded on a score from 0-100. Scores are labelled as: walker’s paradise,

daily errands do not require a car (90-100); very walkable, most errands can be

accomplished on foot (70-89) to car-dependent, almost all errands require a car (0-

24).

• Lake Charles has an average Walk Score of 35 with 71,993 residents.

Sugar-Consumption• High association a high intake of sugar sweetened beverages and the development of obesity.

Odds ratio of becoming obese increased 1.6 times for each additional sugar-sweetened drink

consumed every day.

• One can of soda provides up to 150 kcal and 40–50 g sugar in the form of high-fructose which

is equivalent to 10 teaspoons of table sugar.

• Schulze et al provides strong, scientifically sound evidence that excess calories from soft

drinks are directly contributing to the epidemics of obesity and type 2 diabetes, at least in the

United States, and should help convince the US government that

further changes in health policy are needed. (12)

Salt and Fat• Developed evolutionary trait for humans to crave fat and store as adipose tissue.

Years on… Palatable food is now cheap, fast and not had to be personally hunted!

• With food now readily available (in most countries!), a situation of higher energy

intake is seen.

• High levels of fat increase cholesterol levels in the blood. High low-density

cholesterol is associated with increased stroke, heart attack and blocking of

arteries (atherosclerosis). (13)

Low Density vs High Density Lipoproteins

• Low and high density lipoproteins represent two different cholesterols, with

contrasting roles. Both can also exist in very low density (VLDL) and very high density

(VHDL), which both carry out intensified versions of their prerequisite.

• Low Density Lipoproteins carries cholesterol from your liver to the cells that need it. If

there is too much cholesterol for the cells to use, it can build up in the artery walls.

• This leads to fatty deposits which, over time, reduce or completely block your blood

supply forming an atheroma.

• Atheroma’s have the ability to reduce oxygen delivery to cells. An atheroma in the

the carotid arteries can lead to stroke and potential loss of neural functioning.

Low Density vs High Density Lipoproteins (2)

• Those with higher levels of high density protein levels tend to have fewer

problems with cardiovascular diseases. (14)

• High Density Lipoproteins carries cholesterol from the cells to the liver. Which

then become resynthesized and excreted from the body as bile.

http://blog.wellnessfx.com/2013/10/17/cholesterol-wrong-all-along/

Promotion of Physical Activity

• Physical activity is defined as any bodily movement produced by skeletal muscles

that requires energy expenditure.

• Percent of adults 18 years of age and over who met the Physical Activity

Guidelines for aerobic physical activity: 49.6% (2012). (15)

• Obesity and related comorbidities occur when

energy intake (EI) exceeds energy

expenditure (EE) over time.

• EE is proportional to resting (basal)

metabolic rate and thermogenesis.http://cte.sfasu.edu/wp-content/uploads/2012/01/2_Principles_of_Digestion_and_Metabolism.html

Promotion of Physical Activity (2)

• While energy expenditure can be influenced by keeping energy intake low,

evidence seems to suggest that we are bad predictors of adequate calorific intake.

(16)

• Therefore physical activity could be a useful tool in utilizing excess calories and

combating obesity.

• People still do not meet the recommended 150 minutes of moderate-intensity

aerobic physical activity throughout the week or do at least 75 minutes of

vigorous-intensity.

• Cited reasons usually include lack of quality motivation! (17)

Motivation Within Physical Activity

• Motivation theories may be viewed as being on a continuum for people to range

from total disinterest to complete enjoyment and excitement for PA.

• Lack of motivation can broadly be explained by two orders of factors – people

may not be interested in PA or not value its outcomes.

• Self-determination theory (SDT) has emerged as popular framework.

• SDT explains that people can sit anywhere on the scale from being amotivated,

PA being performed for guilt or external value to enjoyment and internalized

pleasure.

Self –Determination Theory

https://learningsnippets.wordpress.com/tag/self-determination-theory/

Success at Applying Motivational PA Interventions

• People are usually good at forming intentions, but not at performing behavior.

• Low adherence can usually be observed after applying an intervention.

• The goal of motivation interventions is to educate the participant and give skills

to apply by themselves.

• Physical activity interventions are getting better at achieving these goals,

although there is still a long way to go!

Review• Obesity is a multi factorial issue, with a number of interrelated problems that

have created the current epidemic.

• The built environment, lack of cities walkability, high sugar and fat diets, poor

promotion of physical activity, and poor motivational goals could explain some of

this problem.

• In 2010, the Centers for Disease Control and Prevention (CDC) reported higher

numbers once more, counting 35.7% of American adults as obese, and 17%

of American children. (15)

• Still a long way to go!

References1. WHO.INT, (2014). WHO | Obesity and overweight. [online] Available at:

http://www.who.int/mediacentre/factsheets/fs311/en/ [Accessed 30 Oct. 2014].

2. Canadian Medical Association. (2007). 2006 Canadian Clinical Practice Guidelines on the Management

and Prevention of Obesity in Adults and Children. Canadian Medical Association.

3. Yang, W., Kelly, T., & He, J. (2007). Genetic epidemiology of obesity. Epidemiologic reviews, 29 (1), 49-

61.

4. Friedman, J. M. (2003). A war on obesity, not the obese. Science, 299 (5608), 856-858.

5. Mobley, L. R., Root, E. D., Finkelstein, E. A., Khavjou, O., Farris, R. P., & Will, J. C. (2006). Environment,

obesity, and cardiovascular disease risk in low-income women. American journal of preventive

medicine, 30(4), 327-332.

6. Booth, K. M., Pinkston, M. M., & Poston, W. S. C. (2005). Obesity and the built environment. Journal of

the American Dietetic Association, 105(5), 110-117.

7. Duffey, K. J., & Popkin, B. M. (2007). Shifts in patterns and consumption of beverages between 1965 and

2002. Obesity, 15(11), 2739-2747.

8. Andreyeva, T., Kelly, I. R., & Harris, J. L. (2011). Exposure to food advertising on television: associations

with children's fast food and soft drink consumption and obesity. Economics & Human Biology, 9(3), 221-

233.

9. Blair, S. N., & Brodney, S. (1999). Effects of physical inactivity and obesity on morbidity and mortality:

current evidence and research issues. Medicine and science in sports and exercise, 31, S646-S662.

10. Scott MM, Dubowitz T, Cohen DA. Regional differences in walking frequency and BMI: What role does

the built environment play for Blacks and Whites? Health Place. 2009;15:882–7.

11. Brgov.com, (2014). Official Baton Rouge Government Website. [online] Available at:

https://brgov.com/ [Accessed 7 Nov. 2014].

12. Ludwig DS, Peterson KE, Gortmaker SL. Relation between consumption of sugar-sweetened drinks and

childhood obesity: a prospective, observational analysis. Lancet. 2001;357:505-508.

13. NHS.UK, (2014). Is saturated fat bad for me? - Health questions - NHS Choices. [online] Available at:

http://www.nhs.uk/chq/pages/1124.aspx?categoryid=51 [Accessed 19 Nov. 2014].

14. Toth, P. P. (2005). The “good cholesterol” high-density lipoprotein. Circulation,111(5), e89-e91.

15. CDC.GOV, (2014). Fast Stats - Exercise or Physical Activity. [online] Available at:

http://www.cdc.gov/nchs/fastats/exercise.htm [Accessed 19 Nov. 2014].

16. Lichtman, S. W., Pisarska, K., Berman, E. R., Pestone, M., Dowling, H., Offenbacher, E., ... &

Heymsfield, S. B. (1992). Discrepancy between self-reported and actual caloric intake and exercise in obese

subjects. New England Journal of Medicine, 327(27), 1893-1898.

17. Thøgersen-Ntoumani, C., & Ntoumanis, N. (2006). The role of self-determined motivation in the

understanding of exercise-related behaviours, cognitions and physical self-evaluations. Journal of sports

sciences, 24(4), 393-404.