Does Teenage Stress Cause Weight Gain?
Stress is certainly one of the most common factors that is mentioned when patients report “emotional” eating. But how strong a risk factor is perceived stress really for weight gain? This question was addressed by Cornelia van Jaarsveld and colleagues from University College London, UK, in a paper just published in OBESITY. Prospective associations between perceived stress and changes in waist circumference and BMI were examined in data from the Health and Behaviour in Teenagers Study (HABITS), in which height, weight, and waist circumference were measured annually in 4,065 adolescents aged from 11 to 16. In contrast to their expectations, the researchers found that perceived stress in any year was not related prospectively to increases in waist or BMI 1-4 years later, nor was there any evidence that higher stress over the whole period was associated with greater gains in waist or BMI. However, waist and BMI were significantly higher in the moderate- and higher-stress groups than the lower-stress group across the whole 5-year period. Also, persistent stress was associated with higher waist circumference and BMI in adolescence, but did not lead to differential changes over 5 years. This study clearly suggests that the relationship between stress and obesity is more complicated than generally assumed – clearly increased perceived stress does not translate directly into greater weight gain. The authors suggest several reasons for why this relationship may be more complex: 1) Stress can both increase and decrease appetite – thus some people may eat more when stressed, others may stop eating – at a population level this phenomenon can balance out some of the weight risk associated with increased stress levels. 2) Increased weight may result in compensatory behaviours, so that although stress is causing some people to eat more, these people are also more likely to engage in dieting or exercise to manage their weight. 3) Stress may set weight trajectories early in life (e.g. by changing the neural circuitry in their hypothalamus). so that by the time kids reach adolescence (as in this study), their current level of stress may no longer determine or predict their weight status. Thus, in summary, although the study shows that adolescents with higher perceived stress levels tend to be heavier, their current stress levels did not affect their rate of weight gain during the observation period. The authors (and so do I) tend to favor explanation 3 for their findings – this would… Read More »
A Beginner’s Guide to Snoring
Excess weight is commonly associated with sleep disordered breathing, of which obstructive sleep apnea is probably the most dangerous as it has been associated with daytime sleepiness, hypertension, insulin resistance, arrhythmias and sudden death. One of the typical signs of obstructive sleep apnea is snoring – but, as it turns out, snoring is not always a sign of sleep apnea. In fact, as I recently found out in an article published in Parkhurst Exchange, for the purposes of treatment, snoring can be divided into four categories: 1) mouth-breathing 2) nostril collapse 3) tongue base 4) palatal flutter To make things a bit trickier, some patients may have more than one of these problems. Fortunately, simple tests can help identify the problem (The following are taken directly from the Parkhurst publication): Nostril collapse test: in front of a mirror, press the side of one nostril to close it. With the mouth closed, breathe in through the other nostril. If it tends to collapse, try propping it open with a paperclip. If breathing feels easier, nasal dilator strips are probably the answer, such as Breathe Right or Nozovent. Test both nostrils. Mouth-breathing test: make a snoring noise with the mouth open. Then close the mouth and try to make the same noise. If you can’t, mouth breathing is the likely problem, and the likely solution is chin-up strips to hold the mouth closed, or an oral vestibular shield. Tongue test: stick out the tongue and grip it between the teeth, then try to make a loud snoring noise. Failure is a sign of tongue base snoring. The treatment is a mandibular advancement device, which resembles a boxer’s mouthguard. There are expensive customized types, but ‘boil and bite’ moldable models can be just as effective. Palatal flutter: this is vibration of the soft palate and uvula. There’s no test for it, but if the other tests are negative, it’s a likely culprit, especially in patients who aren’t overweight. The commonest treatment is Rhynil spray, made from the astringent herb Euphrasia officinalis. I tried these test on myself but realised that I am not very good at making a snoring noise (at least not while awake). Apparently, there is now some evidence that snoring, even without sleep apnea, can be associated with increased risk for car accidents. And remember, snoring also puts your partner at risk, as they may also suffer increased ill-health as… Read More »
Why The Amount of Food Eaten is as Important as the Amount That is Not
I have previously linked the obesity epidemic to global warming, suggesting that the solution to one of these problems is likely the solution to the other. Here is now another spin to this idea from a study by Kevin Hall and colleagues from the US National Institutes of Health, Bethesda, Maryland, just published in PLoS. Hall and colleagues calculated the energy content of nationwide food waste from the difference between the US food supply and the food consumed by the population. The latter was estimated using a validated mathematical model of metabolism relating body weight to the amount of food eaten. Their calculations show that the US per capita food waste has progressively increased by ~50% since 1974 reaching more than 1400 kcal per person per day or 150 trillion kcal per year (enough to feed ~150 Million additional people). They further estimate that food waste now accounts for more than one quarter of the total freshwater consumption in the US and ~300 million barrels of oil per year (or ~1/3 of Alberta’s annual oil production). In addition to the methane and CO2 emissions from the production of this food that no one needs, even more of these gases are produced as the food decomposes in landfills. The researchers speculate that this increased availability of cheap food creates a “push” effect (now that we’ve gone to the trouble of producing it, let’s make sure it gets eaten), that promotes caloric overconsumption and the development of obesity. As further pointed out in a discussion of this article in the ECONOMIST, “The cheaper food is, the more likely it is to be thrown away even before it is sold to someone who might actually eat it. Such supply-chain waste can be built into the price, and usually makes economic sense. Throwing away leftovers is often better business than risking running out of stock. Yet any waste of a valuable resource is offensive at a visceral level.“ I could not agree more. AMS Edmonton, Alberta Hat tip to Kavita for drawing my attention to this article
The Ups and Downs of Low-Carb Diets
A few weeks ago, while attending the American Heart Association meeting in Orlando, I met with my friend and colleague Steven Smith, who has just taken on the position of Executive Director of the Translational Research Institute for Metabolism and Diabetes, Florida Hospital and Burnham Institute. This week, Steven penned a most interesting essay for the New England Journal of Medicine, in which he discusses potential downsides of a low-carb diet. Most of his argument is based on a recent study that showed progresson of artherosclerotic plaques with a low-carb diet in apolipoprotein E-deficient mice, a model commonly used to study arteriosclerosis. It turns out that the same article was recently also discussed on OBESITY PANACEA, an obesity blog run by Peter Janiszewski and Travis Saunders, two PhD students, who work in obesity research and are very active members of the Canadian Obesity Network. As they point out, the two key possibilities that Steven presents in his article are that increased level of free fatty acids in the blood (released from insulin resistant fat cells and implicated in the initiation of inflammatory processes) or a reduced level of circulating endothelial progenitor cells (produced in bone marrow and help maintain the health of the blood vessels), both possible effects of a low-carb diet, could explain these detrimental effects, but I will leave it to OBESITY PANACEA to explain… AMS Toronto, Canada
Obesity Erodes Smoking Cessation Gains in US
Over the past 15 years, smoking rates in the US have declined by 20%, whereas obesity rates have increased by 48%. A new analysis published in the New England Journal of Medicine by Susan Stewart and colleagues from Harvard University, Boston, MA, forecasts the effect of trends in obesity and smoking on future U.S. life expectancy and quality-adjusted life expectancy. The researchers used data from the past three decades to forecast future rates of obesity and smoking and estimate their effects on length and quality of life. The net effect of the declines in smoking and the increases in BMI for an 18-year old is a reduction in life expectancy of 0.71 years and a reduction in quality-adjusted life expectancy of 0.91 years relative to the trend. This pattern of results is seen for every year between 2005 and 2020 and becomes more pronounced over time. The calculations assume that if past trends continue, almost half the U.S. adult population will meet the WHO criteria for obesity by 2020 (currently the obesity rate already exceeds 35% in some states). Obviously, these forecasts are at a population level and do not apply to a particular person who loses weight or stops smoking. While these results do not imply that life expectancy will fall, they do suggest that as a result of increasing obesity rates life expectancy will rise less rapidly than it otherwise would. While these are US data, there is little reason to assume that similar trends will not also be apparent in other countries including Canada. Clearly, policy makers will likely now need to address obesity with the same vehemence as they did smoking – unfortunately, finding and implementing effective policies to reduce obesity makes smoking bans look like a walk in the park (no pun intended). AMS Edmonton, Alberta
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