Removing the Cause of Weight Gain Does Not Mean Weight Loss
One of the most common misconceptions about obesity management is that identifying and addressing a potential contributor to weight gain should automatically translate into weight loss – it does not! As I pointed out in a recent post, when you identify and address the cause of weight gain – weight gain stops, and that’s usually it! That many of us fail to recognize this rather simple principle, is again illustrated by a paper by Penner and colleagues published in the Journal of Joint and Bone Surgery, which found that successful ankle reconstruction surgery does not decrease BMI in overweight and obese patients. According to their findings, the 145 patients with excess weight who underwent successful ankle replacement or ankle fusion, despite significant improvements in Ankle Osteoarthritis Scale (AOS) scores and increased physical activity scores, pretty much maintained their preoperative BMI levels at six months and one, two, and five years. Based on these findings, the authors conclude that: “Pain and disability are significantly reduced in overweight and obese patients after successful ankle replacement or fusion. Despite this, the mean BMI remains unchanged after the surgery, indicating that weight loss does not commonly occur following successful ankle reconstruction in this patient population. Obesity is likely attributable to factors other than limited mobility caused by ankle arthritis.” Obviously, the authors assumed that if limited mobility caused weight gain, then increasing mobility should reduce it – that, however, is not what happens. Rather, what they found, is exactly what I would expect – with regain of their mobility, patients stopped gaining weight – and that’s all. Without a targeted obesity treatment strategy, there is indeed no reason to expect that these patients would now begin losing weight simply because their activity levels may now be somewhat higher than before. The few extra calories that they may perhaps now burn as a result of being more physically active would easily be compensated by an increased intake or other biological mechanisms that are there to ‘defend’ their current weight. Thus, the observation that successful ankle surgery did not result in ‘spontaneous’ weight loss neither disproves nor proves that pain or disability may have contributed to weight gain in the first place – it probably did in some and probably did not in others. Interestingly enough, I believe that this study also bears an important lesson for those attempting to address obesity at a societal level… Read More »
Close Concerns: Weight Loss and Weight Loss-Maintenance
Earlier this week, the influential healthcare information firm Close Concerns published a rather lengthy interview regarding my take on a wide range of issues related to the future of obesity management. The interviews were conducted by Joseph Shivers, Vincent Wu, Lisa Vance, and Kelly Close, who certainly challenged and stimulated my thinking with their well-informed questions. The following is another brief excerpt from this interview published in their newsletter Closer Look: JOSEPH: The prospect of long-term weight loss in the population as a whole seems very challenging based on most interventions for which we have long-term data. Assuming that we turn this around in the next 50 years, what do the turning points have to be? Will it be better therapy? Some really refined and effective surgery? Impacting childhood obesity? DR. SHARMA: If I had to bet, I’d bet on drugs and not on surgery. I think surgery is a phase. It’s being done now; it’ll be around for probably another decade or so, maybe longer, until we get new drugs. I think that there are two things that may need to change in drug development, or even in the thinking about pharmacological treatment of obesity. The first is starting to differentiate obese people into subsets of obese people. So a drug that doesn’t have to be for whoever has obesity, but rather for a subset of patients with obesity because they have a certain eating disorder or there’s a certain pathway in their brains that is promoting overeating or they have a certain lack of satiety. That is a group of patients for whom a given drug really works. They are the ones who should be getting it. The drug may not work for everybody else. You would start splitting down this whole indication into other groups. That may or may not happen. In hypertension it never happened. We have 100 drugs for hypertension and people have always said, “Let’s break it down and let’s decide who’s the best patient for a diuretic and who’s the best patient for a beta blocker and who’s the best patient for an ACE inhibitor.” That actually never worked. In the end, even today, hypertension practice is pretty much trial and error, with fixed combinations becoming more and more accepted. So, I’m not holding my breath that that will happen with obesity. I think if you find drugs that are overall effective and… Read More »
Weight Bias and Great Expectations
Given that the majority of folks with excess weight face weight bias and discrimination on a regular basis, it is not hard to imagine that the stronger the perceived weight bias, the greater the desire to lose weight. One can also imagine that the lengths and perhaps risks that these individuals will go to, will be far greater than in people who are more comfortable with their excess weight and may have faced less societal pressure. According to a study by Saaqshi Sharma (no relation) and colleagues from Ontario, published in Clinical Obesity, not only does the experience of weight bias apparently drive patients to seek out riskier and more drastic treatments but also perhaps promotes notions of weight loss that are even more unrealistic than harboured by most people seeking obesity treatments. In this study, Sharma and colleagues studied 115 patients of the Wharton Medical Clinic with an average BMI of 40, 85% of who were female and 77% of who reported weight discrimination regarding their weight loss goals as well as their acceptance of different obesity treatments. Specifically, the participants were asked to chose between increasingly ‘severe’ treatment options that they would consider: Severity class I: Lifestyle changes (i.e. eat less, eat better, more physical activity, more will-power) Severity class II: Pharmacotherapy and meal replacements Severity class III: Bariatric surgery Severity class IV: Genetic modification (i.e. something that is currently not even possible) Overall, participants considered a weight loss of about 33% (or about 38 Kg) as ‘ideal’ and the majority thought that this could be achieved through lifestyle changes such as improved physical activity (80%) or diet (52%), with fewer reporting pharmacotherapy (8%), surgery (12%) or genetic modification (7%) as necessary for achieving this degree of weight loss. Thus, participants selecting lifestyle changes or pharmacotherapy for weight loss reported ideal weight loss goals that would generally only be achievable through surgical means (i.e. 32% and 33%, respectively), and participants selecting surgical intervention reported ideal goals at the upper end of what is generally achievable even with surgery (38%). Participants selecting surgery or genetic modifications were also more likely to report experiencing weight discrimination. These findings have two important messages, which although perhaps not unexpected, should provide pause for discussion. Firstly, it is evident that patients (and perhaps many health professionals) vastly overestimate the weight loss results of lifestyle interventions – an average outcome for these are in… Read More »
Will Exercise Make You Fat?
Yesterday, I had the pleasure of hosting John Blundell, at the Research in Progress seminar series at the Alberta Diabetes Institute. Dr. Blundell is Professor of bio-psychology at the University of Leeds, UK, and is certainly one of the preeminent authorities on the bio-psychology of ingestive behaviour. His presentation with the rather provocative title, “Will exercise make you fat?”, started with a broadside at the media, which lately has been quite active in promoting this notion. However, as Blundell pointed out, this simplistic message is far from accurate in that the relationship between physical activity and its impact on ingestive behaviour and body weight is anything but straightforward. For one, although short-term studies (days) do often show an increase in appetite, this is by no means regularly observed in longer-term studies (weeks). In a paper he recently published in the Journal of Clinical Endocrinology and Metabolism, Blundell recently examined the effects of medium-term exercise on fasting and post-prandial levels of appetite-related hormones and subjective appetite sensations in overweight and obese individuals. The study included 22 sedentary individuals who took part in a 12-wk supervised exercise programme (five times per week, 75% maximal heart rate) and were requested not to change their food intake during the study. Not only did exercise result in a significant, albeit modest (~3 Kg), reduction in body weight and fasting insulin and an increase in ghrelin plasma levels but also in a reduction in fasting hunger sensations. A significant reduction in postprandial insulin plasma levels and a tendency toward an increase in the delayed release of glucagon-like peptide-1 (90-180 min) and a greater suppression of postprandial ghrelin. Thus, although exercise-induced weight loss was associated with physiological and biopsychological changes towards an increased drive to eat in the fasting state, this compensatory effect seems to be balanced by an improved satiety response to a meal and improved sensitivity of the appetite control system. However, as Blundell pointed out, these mean changes hide the immense diversity between individuals. Based on these studies it appears impossible to predict in advance how individuals will respond: Some people, in response to exercise, will be hungry and may overeat – others may find that they are much better in controlling their food intake. Importantly, all subjects, irrespective of their body weight, showed a reduction in their amount of body fat and improvements in risk markers like physical fitness and blood pressure. Thus,… Read More »
How Effective is Resistance Training for Weight Loss?
While there is no doubt that exercise is an important part of long-term weight management the exact role of resistance training (as opposed to aerobic or endurance training) remains unclear. A paper by Barbara Strasser and colleagues from the University of Hall i. T., Austria, just published in Sports Medicine, describes a systematic review and meta-analysis of the effect of resistance training on metabolic risk factors in patients with abnormal glucose metabolism. The authors identified 13 randomised controlled trials (RCTs) published between January 1990 to September 2007. The number of participants in the individuals studies ranged between 17 to 120, with a pooled total of 425 participants in studies reporting HbA1c; of these, 219 participants received the resistance intervention. The mean age of the groups was between 46.8 and 67.6 years. While resistance training reduced glycosylated haemoglobin (HbA(1c)) by 0.48%, fat mass by 2.33 kg and systolic blood pressure by 6.2 mmHg, it had no statistically significant effect on total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride or diastolic blood pressure. The authors concluded that resistance training has clinically significant effects on various components of the metabolic syndrome and should therefore be recommended in the management of type 2 diabetes and obesity. While the paper only reports the effect of resistance training on fat mass (and not body weight), it does allude to the fact that participants also increased muscle mass, which will likely have made the actual change in body weight even smaller than the rather modest reduction in fat mass (~5 lbs). Nevertheless, given the positive effects on glucose metabolism and blood pressure, these findings should certainly not discourage people from engaging in a reasonable amount of resistance training, even if the benefits are perhaps not measurable on a scale. AMS Toronto, Ontario p.s. Join my new Facebook page for more posts and links on obesity prevention and management Strasser B, Siebert U, & Schobersberger W (2010). Resistance training in the treatment of the metabolic syndrome: a systematic review and meta-analysis of the effect of resistance training on metabolic clustering in patients with abnormal glucose metabolism. Sports medicine (Auckland, N.Z.), 40 (5), 397-415 PMID: 20433212
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