Cold Exposure Promotes Gut Microbes That Stimulate Brown Fat
It seems that there is no end to how intimately gut microbes are linked to metabolic function. Thus, a study by Claire Chevalier and colleagues from Geneva, Switzerland, published in CELL, not only shows that cold exposure (of mice) changes their gut microbes but also that, when transplanted into sterile mice, these “cold” microbes stimulate the formation of thermogenic brown fat. All of this makes evolutionary sense, as the increase in heat-generating (and calorie-burning) brown fat with cold exposure would protect the organism against cold exposure – however, that gut bacteria would be involved in this process is indeed rather surprising. Unfortunately, at least for those thinking that “cold bacteria” may be the panacea for stimulating brown fat and thus weight loss are likely to be disappointed. The researchers also show that with prolonged exposure to cold, these “cold bacteria” induce changes to the structure and function of the gut that enable more glucose to be absorbed. While in the short-term, this extra fuel can be used by the brown fat to generate heat, in the long-term, some of these extra calories probably go towards building more white fat and thus weight gain. Again, this makes evolutionary sense. After all, it is ecologically a far better strategy to insulate the house than to waste extra calories heating it. This is why, the naive notion that simply lowering ambient temperature as a means to generate more brown fat and thus, burn more calories, may not be all that effective. Indeed, these experiments suggest rather that chronic cold exposure would ultimately stimulate extra insulation, i.e. more subcutaneous fat and weight gain. Funnily enough, these findings turn the hypothesis that reducing room temperature would promote weight loss into exactly the opposite. Perhaps it is the excessive use of air-conditioning to generate freezing indoor temperatures (as any European visitor to the US will readily attest to), is part of the problem. Fascinating stuff for sure. @DrSharma Gurgaon, Haryana
Just How Much Weight Do You Gain When You Stop Smoking?
The fact that smoking cessation is almost regularly associated with weight gain is common knowledge. But just how much weight can one expect to gain? Now, an analysis from a large randomised controlled trial of smoking cessation by Charles Courtemanche and colleagues published for the National Bureau of Economic Research, that this weight gain may be more that most people think. The researchers look at data from well over 5,000 participants in the Lung Health Study. Using various statistical models, they conclude that the average weight gain is about 12 pounds, with the effect being greatest in the young, women and those starting out with a ‘normal’ weight. They also calculate that the reduction in smoking over the past decades accounts for about 15% of the obesity epidemic. From the longitudinal analysis they also conclude that the weight gain is not temporary nor likely reversible. If anything, the impact of smoking cessation on weight becomes greater as time passes. Thus, while the authors remind us that the benefits of smoking cessation on health still by far outweigh any health detriments from a 12 lb weight gain. Nevertheless, the data should remind us that smoking cessations efforts should always go hand in hand with efforts to prevent excessive weight gain. @DrSharma Gurgaon, Haryana
Does Bariatric Surgery Reset The Setpoint?
As readers are well aware, the crux of the obesity problem is that the body tends to defend it’s highest body weight. This is why anytime you try to lose weight, the complex neuroendocrine kick in to try to “sabotage” your efforts and seemingly won’t rest till the weight is regained. So why does bariatric surgery work? Why do people who undergo bariatric surgery not simply eat back the extra calories required regain all of the weight they lost in the first year after surgery? One of the notions is that the surgery itself makes it hard to overeat (restriction) or works by interfering with digestion (malabsorption) – but there is now increasing evidence that neither of these mechanisms appear to be the real reason surgery is so successful. Now, a study by Zheng Hao and colleagues from Baton Rouge, LA, published in OBESITY, provides evidence to support the idea that gastric bypass surgery may produce favourable long-term outcomes by reprogramming the way that they body regulates its weight. The studies (performed in mice), show that after Roux-en-Y gastric bypass surgery, the animals begin to regulate body weight at a level that is lower than before surgery. What was most surprising in these experiments, was that mice which were starved down to a rather low weight before surgery, actually regained weight after surgery (albeit to a weight that is still well below where they would have been before the experiment) and that this weight gain was mainly due to an increase in lean-body mass. This response is very different from animals (or humans) regaining weight after dietary caloric restriction, where most of the weight gain is due to an increase in fat mass. Thus, it seems that the neuroendocrine alterations that happen with surgery, trigger mechanisms that appear to defend against a higher level of body fat, while remaining sensitive to the defense of lean mass. How exactly this works remains unclear but the hope is that by better understanding the molecular and physiological mechanisms underlying this reprogramming we may be able to develop medications that will mimic the effects of surgery. @DrSharma Edmonton, AB
Can Metformin Reduce Weight Gain In Pregnancy?
Excessive weight gain during pregnancy is a well-established risk factor for both mother and child. Now a paper by Argyro Syngelaki and colleagues from the UK, published in the New England Journal of Medicine, suggests that the anti-diabetes drug metformin may limit weight gain in pregnant non-diabetic women with obesity and also reduce the incidence of pre-eclampsia. The researchers randomised 450 pregnant women with a BMI greater than 35 and no diabetes to either metformin (3 g/day) or placebo from weeks 12-18 weeks of gestation till delivery in a double-blind fashion. Among the 400 women who completed the study, those on metformin gained about 2 Kg less weight than the placebo group. There was also an almost 75% decrease in the risk of developing preeclampsia. Despite these effects, metformin did not significantly reduce the incidence of large-for-gestational-age babies or other adverse neonatal outcomes. While these findings may be somewhat disappointing with regard to outcomes in the offspring, the reduction in pre-eclampsia is impressive and, if confirmed, could well be an interesting use of this compound in high-risk pregnancies. @DrSharma Kelowna, BC
If Oprah Can’t Why Do You Think You Can?
There are no doubt long-term “success stories” out there – people who just by making (often radical) changes in their diet and activity behaviours have lost a substantial amount of weight AND are keeping it off. However, there is also no doubt that these people are rare and far between – which is exactly what makes each one of them so exceptional. I am not speaking of all the people we hear or read about who have lost tons of weight – we hear about their spectacular weight loss – cutting carbs, cutting gluten, going vegan, going paleo, alternate day fasting, running marathons, training for iron man competitions, going on the Biggest Loser or eating at Subway. What we don’t hear about is the same people, when they put the weight back on – which, in real life is exactly what happens to the absolutely vast majority of “losers”. We hear of their “success” and then we never hear from them again – ever. Oprah is different! Different because, we have had the opportunity to follow her ups and downs over decades. When Oprah “succeeds” in losing weight, she does not disappear into the night – no – she puts the weight back right in front of our eyes, again and again and again and again. Now, comedy writer Caissie St.Onge, in a comment posted on facebook, pretty much summarizes what it is we can all learn (and should probably have learnt a long time ago) from Oprah: “Oprah is arguably the most accomplished, admired, able person in the world. She creates magic for other people and herself on the regular. So, if Oprah can’t do permanent lifelong weight loss, maybe it can’t be done. Oprah is also crazy rich. If Oprah can’t buy permanent lifelong weight loss, maybe it can’t be bought.” “I’m not saying you should give up on your dreams of having the body you want. I’m just asking, if you never get that waist, will your life have been a waste? (I see what I did there.) Every day we are bombarded with media, content and products. Special foods and drinks. Programs and plans. None of this shit has ever worked for Oprah and it probably isn’t gonna work for me or you.” “I know the reason isn’t because you’re weak. If you’re carrying around 10 or 20, or 50 or 150 pounds more than the tiny… Read More »
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