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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.
Obesity Panacea
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by Travis Saunders, MSc in Obesity Panacea
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 »
Saunders, T. (2011) Potential Contributors to the Canadian Pediatric Obesity Epidemic. ISRN Pediatrics, 1-10. DOI: 10.5402/2011/917684
by Travis Saunders, MSc, CEP in Obesity Panacea
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 assessed for a fourth time, allowing the researchers to compare the influence of 3 weeks of bed rest and 30 years of aging on markers of fitness.... 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
by Travis Saunders, MSc in Obesity Panacea
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 Citizen article. But the article is actually very well written, and includes interviews with a number of excellent researchers (including Bob Ross, who supervised my MSc, and Tim Church, who has co-authored papers with both Peter and I), as well as physician Yoni Freedhoff of Weighty Matters. Since this issue comes up so frequently, and because of its public health importance, I thought this would be an excellent opportunity to "weigh in" with my opinion.
So, does exercise reduce body weight? To be completely honest, it depends on the situation. Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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% success rate", but we thought it best to review the evidence before making a judgement one way or the other.
The use of HCG to treat obesity was first suggested by ATW Simeons in a 1954 Lancet paper. He reported that injection of HCG resulted in rapid mobilization of body fat stores and induced feelings of well-being. He also claimed that HCG reduced weakness and hunger during very low calorie diets (500kcal/day) and that HCG treatment could be used to prevent the protein and vitamin deficiencies which are a frequent side-effect of such low caloric intake. Finally, he suggested that HCG could be used to successfully treat a range of ailments ranging from diabetes and gout to ulcers and skin diseases. However, it is important to note that no actual study was performed - these were just subjective observations. Naturally, Simeons' observations spurred actual research into HCG.
Unfortunately for Simeons' pet theory, the vast preponderance of studies examining the effectiveness of HCG in the treatment of obesity found absolutely no effect. For example, a 1976 paper in the Journal of the American Medical Association performed a rigorously controlled, double-blind crossover study examining the effects of HCG on weight loss in obese individuals undergoing very low calorie diets. In a double-blind study, neither the patient, nor the physician, knows whether the patient is receiving HCG or a placebo. What were their results? Both groups lost a significant amount of weight (not surprising given subjects were only consuming 500 kcal/day), however there was no difference in weight loss between the HCG and placebo treatments. Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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 creation of updated, and increasingly evidence-based guidelines. ... 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
by Travis Saunders, MSc in Obesity Panacea
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 Davidson suggests once-again that exercise can also prevent the accumulation of abdominal fat, independent of changes in overall body fat percentage.... 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:/
by Travis Saunders, MSc in Obesity Panacea
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 that there is a news story reporting that the obesity epidemic is caused by diet. Period. If you believe these articles, physical activity plays a minor role, if any role at all. Some have even (erroneously) suggested that physical activity increases the risk of weight gain (for a thorough debunking of a recent TIME article on this subject, click here).
One of the problems of trying to untangle the role of physical activity in the development of obesity is that most studies use indirect measures of physical activity, like self-report questionnaires. Not surprisingly, there is a lot of error when people are reporting a socially-desirable behaviour like physical activity, as they tend to err on the positive side. And questionnaires also often give several fixed options, for example "Are you normally active for 15, 30, 45, or 60 minutes per day?". If you are active for 20 minutes per day, would you pick 15 or 30? Either way, it introduces a lot of error, which makes it very difficult to determine the specific role that your current physical activity levels play in the development of obesity down the road.
Read the rest of this post... | Read the comments on this post...... 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 Travis Saunders, MSc in Obesity Panacea
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 elevated metabolic risk factors, meanwhile others who can apparently indefinitely grow more fat mass (multiple symmetric lipomatosis - think Michelin man) have metabolic profiles we'd all like to have. Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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 cardiovascular disease - exactly what we are trying to prevent in the first place. So this raises the important question - in order to minimize the risk of heart disease, is it better to reduce the intake of saturated fat, or the intake of simple carbs? An interesting new study in the American Journal of Clinical Nutrition examines this issue and while it doesn't provide a definitive answer, it suggests that refined carbs are pretty bad indeed.... 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
by Travis Saunders, MSc in Obesity Panacea
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 your body's defense against the worst effects of unhealthy eating, rather than their direct cause.
While the article goes on to discuss some interesting new research, I feel the author misses an opportunity to really challenge the overwhelming dogma that too much fat, per se, is the cause of metabolic consequence of obesity. From my experience, it is much easier to get the point across by investigating the obvious anomalies or outliers to the often thought direct relationship between excess adiposity and disease.... 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
by Travis Saunders, MSc in Obesity Panacea
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 purchases to those healthier options. But a very interesting new study by Leonard Epstein and colleagues suggests that things might not be so simple.... 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
by Travis Saunders, MSc in Obesity Panacea
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 very likely to reduce your risk for diseases like diabetes and cardiovascular disease. It's still uncertain if this light intensity physical activity can reduce body weight, but it is clear that individuals who engage in high amounts of light intensity physical activity are healthier than those who do not. In fact, there is good evidence to suggest that simply reducing the amount of time spent sitting each day may reduce risk of death independently of other lifestyle factors (for my recent post on this topic, click here).
Peter and I have discussed the importance of daily physical activity in several posts over the past few months, so today we have decided to offer some practical ways that you can incorporate physical activity into your daily life. These are tips that we have found work well for us, and we think they may work well for you as well. Try one or two, and once they've become part of your routine try a couple more. We would also love to hear your own tips in the comments section below.
Withour further ado, here are ten simple ways to become more physically active:
1. Take the stairs as often as possible.
This one is as simple as it sounds. If you have to go up two floors or less, opt for the stairs. Ditto if you have to go down three floors or less. If you have to go up or down a distance that is too great for you to walk at the moment, walk the first few flights, then take the elevator the rest of the way. Remember, every time you take the stairs instead of the elevator or escalator, you are making a decision that will positively affect your long term health.
2. Drink plenty of water.
This sounds odd, but it's a trick that I've been using for years. If you are constantly sipping water throughout the day, you are going to have to pee at least once an hour. Every time you have to pee, you have a guilt-free excuse to go for a 5-minute walk to the washroom and back! To crank it up a notch, use a washroom in another part of your building, which may give you an opportunity to use the stairs as well. It's easy to forget to take a 5-minute walk-break every hour, but it's impossible to forget to go pee.
Added bonus - staying well hydrated may also reduce feelings of hunger, and can often reduce chronic back pain. So this is really a win-win-win.
Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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 people are enthralled with the Nintendo Wii as a means of increasing childhood physical activity - even though it is expensive, and the evidence supporting it is weak at best. At the same time, evidence continues to accumulate in support of simple, inexpensive interventions for increasing childhood physical activity. Today I'd like to briefly look at one of the simplest possible ways of increasing childhood physical activity levels - painting lines on a schoolyard playground.... 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
by Travis Saunders, MSc in Obesity Panacea
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.
The study is titled "The influence of exercise and BMI on injuries and illnesses in overweight and obese individuals: a randomized control trial" and was performed by Carol Janney and John Jakicic at the University of Pittsburgh. Participants in the study included overweight and obese individuals taking part in one of two exercise studies - one focused weight loss and the other on weight maintenance. The exercise component of the two studies were similar, with participants walking at a brisk pace 5 days/week (the major difference between the two studies is that one included caloric restriction to induce weight loss, while the other simply emphasized healthy eating patterns). Every 6 months, participants reported any injuries or illnesses that impacted their ability to exercise.
Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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 »
Saunders, T. (2011) Potential Contributors to the Canadian Pediatric Obesity Epidemic. ISRN Pediatrics, 1-10. DOI: 10.5402/2011/917684
by Travis Saunders, MSc in Obesity Panacea
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 »
Saunders, T. (2011) Potential Contributors to the Canadian Pediatric Obesity Epidemic. ISRN Pediatrics, 1-10. DOI: 10.5402/2011/917684
by Travis Saunders, MSc in Obesity Panacea
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 guidelines, since transit trips almost always involve some walking on either end of the trip (for more info on the transit/physical activity link, click here).... 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
by Travis Saunders, MSc in Obesity Panacea
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 culminated in both a hot-off-the-press publication in the journal Obesity, as well as my presentation at this year's Obesity Society meeting in Washington D.C.
In the study, we used body composition data acquired through MRI on about 100 premenopausal women to directly quantify breast size. By using MRI data we significantly improved the methodology used by the authors of the original study on breast size and diabetes risk, who relied on over 20 year recall of cup size as their key measure.
First, we sought to examine if breast tissue volume was associated with any cardiometabolic risk factors, such as glucose tolerance (a known antecedent to type 2 diabetes) and various blood lipids. Since the original authors found an association between cup size and diabetes risk, we expected to find an association between breast volume and cardiometabolic risk factors.
What did we actually find? Read the rest of this post... | Read the comments on this post...... 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
by Travis Saunders, MSc in Obesity Panacea
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 podcast was inspired by a recent conversation where I bemoaned a press release which failed to acknowledge the limitations of self-report data, which I felt could lead to misleading conclusions.... 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
by Travis Saunders, MSc in Obesity Panacea
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 illness."
However, there still remains the issue of various musculo-skeletal problems which appear to happen at a high rate among those individuals carrying excess weight, independent of their activity level.Knee and hip osteoarthritis, for example, are quite commonly listed as a frequent medical consequence of obesity. A new study from our neck of the woods (Ontario, Canada) sought to determine the effect of weight status on the age at which individuals elected to have knee or hip replacement surgery.
Read the rest of this post... | Read the comments on this post...... 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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