117 posts · 123,759 views
Travis Saunders and Peter Janiszewski are PhD students in Exercise and Health Physiology at Queen's University in Ontario, Canada. Their research focuses on obesity, body composition, physical activity, nutrition and metabolic health.
In Part 1 we examined the impact of changes in physical activity and sedentary behaviour, and in Part 2 we looked at changes in food intake. Today we look at the evidence (or lack thereof) linking sleep, pollution, maternal age and breastfeeding with the pediatric obesity epidemic.... Read more »
Today we will look at other potential contributors to the pediatric obesity epidemic which I didn’t include in my paper. There are a few reasons for that – some risk factors are ones that I just felt didn’t have much evidence behind them, others were similar to ones that were included, and some just didn’t fit within the space constraints (since this paper was originally written for my comprehensive exams, it was limited to 15 pages).... Read more »
In Part 1 we examined the impact of changes in physical activity and sedentary behaviour, in Part 2 we looked at changes in food intake, and in Part 3 we looked at sleep, breastfeeding, maternal age and pollution. Today we look at the evidence (or lack thereof) linking adult obesity with the pediatric obesity epidemic, then examine the relative contributions of all of the risk factors we’ve discussed so far.... Read more »
I recently came across a very interesting study published in Circulation in 2001. In it, authors Darren McGuire and colleagues perform the 30-year follow-up on a group of 5 men who had taken part in the Dallas Bed Rest and Training Study (DBRTS). The DBRTS took place in 1966, when all 5 men were healthy 20 year-olds. They were assessed extensively at 3 different time points: baseline, following 3 months of bed rest, and following 8 weeks of physical training. In 1996 these same 5 men were as........ Read more »
McGuire DK, Levine BD, Williamson JW, Snell PG, Blomqvist CG, Saltin B, & Mitchell JH. (2001) A 30-year follow-up of the Dallas Bedrest and Training Study: I. Effect of age on the cardiovascular response to exercise. Circulation, 104(12), 1350-7. PMID: 11560849
Photo by Todd Huffman.
One of the great things about this site is that people often bring products or research to our attention that we otherwise might have missed. This occurred yesterday in the comments section of Peter's recent post on Acai berry scams, when one of our readers brought up the use of Human Chorionic Gonadotropin (HCG) in the treatment of obesity. The website that we were provided smacks of weight loss gimmickry - notably the promise of an obesity "cure" and "near 100% ........ Read more »
Lijesen GK, Theeuwen I, Assendelft WJ, & Van Der Wal G. (1995) The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis. British journal of clinical pharmacology, 40(3), 237-43. PMID: 8527285
Image by atomicjeep
I came across a very interesting article in the Ottawa Citizen this weekend, unpleasantly titled "For Canada's obese, exercise alone isn't going to cut it". The crux of the article is this - exercise will not help you lose weight. Every few months it seems that this issue pops up, including a cover article in TIME magazine last year, which Peter has previously dissected. This is a complicated issue, and given the sensational title, I wasn't expecting much from the Cit........ Read more »
Church, T., Earnest, C., Skinner, J., & Blair, S. (2007) Effects of Different Doses of Physical Activity on Cardiorespiratory Fitness Among Sedentary, Overweight or Obese Postmenopausal Women With Elevated Blood Pressure: A Randomized Controlled Trial. JAMA: The Journal of the American Medical Association, 297(19), 2081-2091. DOI: 10.1001/jama.297.19.2081
Ross R, Dagnone D, Jones PJ, Smith H, Paddags A, Hudson R, & Janssen I. (2000) Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial. Annals of internal medicine, 133(2), 92-103. PMID: 10896648
One of the most interesting things about exercise is that it results in important health improvements even in the absence of weight loss. For example, just a single session of exercise can result in improved insulin sensitivity, increased levels of HDL cholesterol (aka the "good" cholesterol) and reductions in plasma triglyceride levels - all tremendously important markers of disease risk. In addition to these metabolic changes, new research by our friend and former labmate Lance Dav........ Read more »
Davidson, LE, Tucker, L, & Peterson, T. (2010) Physical Activity Changes Predict Abdominal Fat Change in Midlife Women. Journal of Physical Activity and Health. info:/
Last week ParticipACTION and the Canadian Society for Exercise Physiology (CSEP) released recommendations for updated Canadian Physical Activity Guidelines. The previous guidelines were released between 1998 and 2002, and although they were based on the best research available at the time, from what I understand there simply wasn't a tremendous amount of evidence to draw on in some situations. Since then there have been a number of advances in physical activity research, allowing for the........ Read more »
Janssen I, & Leblanc AG. (2010) Systematic review of the health benefits of physical activity and fitness in school-aged children and youth. The international journal of behavioral nutrition and physical activity, 7(1), 40. PMID: 20459784
Over the next few months, Peter and I will be re-posting some of our favourite posts from our Obesity Panacea archives. The following article was originally posted on December 2, 2009.
Image by Mike Baird.
There is a surprising amount of controversy about the ability of physical activity to prevent the development of obesity. Sure, obese individuals tend to perform less physical activity than their lean counterparts, but that doesn't prove causation. And almost every week it seems th........ Read more »
Riddoch, C., Leary, S., Ness, A., Blair, S., Deere, K., Mattocks, C., Griffiths, A., Davey Smith, G., & Tilling, K. (2009) Prospective associations between objective measures of physical activity and fat mass in 12-14 year old children: the Avon Longitudinal Study of Parents and Children (ALSPAC). BMJ, 339(nov26 2). DOI: 10.1136/bmj.b4544
By now, readers of Obesity Panacea have hopefully learned that excess weight is not directly predictive of health risk, and that excess fat mass is not in itself unhealthy. Recall that approximately 30% of individuals who are classified as obese by their body weight turn out to be metabolically healthy, and in fact seem not to get much metabolic benefit (or may even get worse) when they lose weight. Also consider that individuals who have NO fat tissue (e.g. lipodystrophy) have extremely elevat........ Read more »
McLaughlin, T., Liu, T., Yee, G., Abbasi, F., Lamendola, C., Reaven, G., Tsao, P., Cushman, S., & Sherman, A. (2009) Pioglitazone Increases the Proportion of Small Cells in Human Abdominal Subcutaneous Adipose Tissue. Obesity. DOI: 10.1038/oby.2009.380
Photo by pugetsoundphotowalks.
Regardless of your shape or size, physical activity has been shown to add years to your life, and life to your years. But believe it or not, the benefits of physical activity are not restricted to exercise performed in the gym. In fact, one of the easiest ways to improve your health may be through increasing the amount of low intensity physical activity you perform throughout the day. For example, simply increasing the number of steps that you take each day is ........ Read more »
Ekelund, U., Brage, S., Froberg, K., Harro, M., Anderssen, S., Sardinha, L., Riddoch, C., & Andersen, L. (2006) TV Viewing and Physical Activity Are Independently Associated with Metabolic Risk in Children: The European Youth Heart Study. PLoS Medicine, 3(12). DOI: 10.1371/journal.pmed.0030488
Lachapelle, U., & Frank, L. (2009) Transit and Health: Mode of Transport, Employer-Sponsored Public Transit Pass Programs, and Physical Activity. Journal of Public Health Policy. DOI: 10.1057/jphp.2008.52
In the past few years several prominent researchers have argued for the adoption of taxes on junk food as a means of reducing their consumption. Often, as in a recent editorial in the New England Journal of Medicine, the argument is made that money collected through the tax could then be used to subsidize healthier foods. This is an idea that I've found very appealing - we make the bad foods more expensive, the good foods less expensive, and people will probably shift at least some of their p........ Read more »
Epstein, L., Dearing, K., Roba, L., & Finkelstein, E. (2010) The Influence of Taxes and Subsidies on Energy Purchased in an Experimental Purchasing Study. Psychological Science, 21(3), 406-414. DOI: 10.1177/0956797610361446
That's right - contrary to what many religiously believe, it is the inability to grow more fat during times of energy surpluss, rather than the excess of fat which appears to directly contribute to the metabolic consequence often associated with obesity.
A recent article in the New Scientist shines some light on this issue;
Obesity kills, everyone knows that. But is it possible that we've been looking at the problem in the wrong way? It seems getting fatter may be part of........ Read more »
Bays, H., & Dujovne, C. (2006) Adiposopathy is a more rational treatment target for metabolic disease than obesity alone. Current Atherosclerosis Reports, 8(2), 144-156. DOI: 10.1007/s11883-006-0052-6
Most people know that consuming too much fat, and especially saturated fat, is bad for your health. That's why there has been a concerted push for several decades to get people to reduce the amount of saturated fat that they consume, and to replace it with complex carbohydrates. Now unfortunately people often misinterpret that to mean that fat is evil, but carbs are ok. This is problematic since consuming too many simple carbs is also likely to increase the risk of obesity, diabetes, and ........ Read more »
Hu FB. (2010) Are refined carbohydrates worse than saturated fat?. The American journal of clinical nutrition, 91(6), 1541-2. PMID: 20410095
Jakobsen MU, Dethlefsen C, Joensen AM, Stegger J, Tjønneland A, Schmidt EB, & Overvad K. (2010) Intake of carbohydrates compared with intake of saturated fatty acids and risk of myocardial infarction: importance of the glycemic index. The American journal of clinical nutrition, 91(6), 1764-8. PMID: 20375186
Regular readers of Obesity Panacea will know that I am a huge fan of active transportation (e.g. walking or cycling to work, rather than commuting by vehicle). I just can't say enough good things about it. It often takes about the same amount of time as commuting by vehicle, plus it ensures that you're getting at least some physical activity on even the busiest days. Even just taking transit instead of driving yourself increases your chances of meeting the daily physical activity gu........ Read more »
Wilkinson, P., Smith, K., Davies, M., Adair, H., Armstrong, B., Barrett, M., Bruce, N., Haines, A., Hamilton, I., & Oreszczyn, T. (2009) Public health benefits of strategies to reduce greenhouse-gas emissions: household energy. The Lancet, 374(9705), 1917-1929. DOI: 10.1016/S0140-6736(09)61713-X
Image by Jespahjoy.
Just before moving to our new home here on Scienceblogs, I asked our readers for ideas on what types of content they would like to see here on Obesity Panacea. One topic that came up several times was the issue of injuries. I'm not sure why we haven't discussed injuries in the past (aside from the fact that it's not the focus of our research), but it was a great idea, and I've come across a study on the topic that I think will be of real interest.
........ Read more »
Janney, C., & Jakicic, J. (2010) The influence of exercise and BMI on injuries and illnesses in overweight and obese adults: a randomized control trial. International Journal of Behavioral Nutrition and Physical Activity, 7(1), 1. DOI: 10.1186/1479-5868-7-1
In most developed nations, kids get far less physical activity than they did just a few generations ago. Given the strong links between physical inactivity and health risk (and given that we're now seeing "adult" diseases like heart disease and type 2 diabetes in children and teenagers), this has become a very real public health concern. Unfortunately, when it comes to increasing childhood physical activity levels, people often want to reinvent the wheel. For example, many peop........ Read more »
STRATTON, G., & MULLAN, E. (2005) The effect of multicolor playground markings on children's physical activity level during recess. Preventive Medicine, 41(5-6), 828-833. DOI: 10.1016/j.ypmed.2005.07.009
Regular readers know that that Peter and I do a semi-regular podcast on obesity-related issues. This week, I have a discussion with psychology researcher (and fellow ScienceBlogger) Jason Goldman. For the uninitiated, self-report data refers to information that people provide themselves - questionnaires and interviews are very common examples. This is in contrast to direct measurement, which is exactly what it sounds like - researchers measuring your height and weight themselves, etc. The po........ Read more »
Schwarz, N. (1999) Self-reports: How the questions shape the answers. American Psychologist, 54(2), 93-105. DOI: 10.1037//0003-066X.54.2.93
In June of last year, I discussed the results of a large epidemiological study in women that showed that women with larger breasts have an increased risk of developing type-2 diabetes.
As soon as Travis and I read this study, we knew we had to do a follow-up study of our own to see if this finding was simply spurious or if there was actually something to large breasts that indicated health risk - beyond that explained by obesity per se.
The project that Travis and I began over a year ago has ........ Read more »
Janiszewski, P., Saunders, T., & Ross, R. (2009) Breast Volume is an Independent Predictor of Visceral and Ectopic Fat in Premenopausal Women. Obesity. DOI: 10.1038/oby.2009.336
Given that I have put myself out of commission due to a musculoskeletal injury I acquired over the weekend, I thought a discussion of joint injuries and such would be most appropriate in my Robaxocet induced state.Just last week Travis discussed the issue of injuries associated with exercise among obese individuals. In that post, based on recent evidence, Travis concluded:"...in overweight and obese individuals, exercise (in the form of walking) has little or no association with injury or illn........ Read more »
Gandhi, R., Wasserstein, D., Razak, F., Davey, J., & Mahomed, N. (2010) BMI Independently Predicts Younger Age at Hip and Knee Replacement. Obesity. DOI: 10.1038/oby.2010.72
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