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Archive for the ‘Research’ Category

Quote of the day

Canadian obesity doc/researcher/professor Dr. Arya Sharma has the results of a new meta-analysis of 37 RCTs looking at behavioral interventions and weight loss. The result? Not exactly promising … ~5 pounds weight lost over 12 months.

On calorie counting:

[T]here is enough evidence in the literature to show that most “successful” dieters develop a somewhat obsessive relationship to accounting for every bite they put in their mouths – measuring, counting, adding, journaling, avoiding and restricting become part of their daily routine. For some it becomes so automatic a behaviour, that they are no longer even conscious of doing it (nor do many stop to realise just how “abnormal” such a behaviour actual is).

If this helps them better manage their weight – good for them. As a strategy for the population – or in other words when measured in terms of “effectiveness” – such an approach is bound to fail. This is because most people are simply not going to live their lives that way (and who can blame them?).

On behavioral interventions and weight loss (emphasis mine):

This is not to say that behavioural interventions in obese individuals (including physical activity) are not beneficial – they are, just not for weight loss.

As I have said before (and restate every time I get a chance) – improving health behaviours can certainly lead to a healthier you – whether that you is leaner or not is an entirely different (and less important?) question.

It turns out that getting your cortex to run your hypothalamus is far more difficult that you may think.

While I’m not sure I’m on board with all of Dr. Sharma’s approaches to obesity (he’s not opposed to interventions like weight loss surgery or prescription drugs), I think the point about looking at this at a population level is important. Not everyone is ready or able to do a VLF or VLC diet and/or avoid grains or dairy or meat and/or turn into Michael Pollan and start cooking every meal and/or do weight loss surgery.

IMO, that’s what makes it a cultural or societal issue.

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I hope you’ll all head over to Healthy Urban Kitchen to read Sarah Lord’s guest post on the recent meta-analysis about whether or not you can be healthy and obese. Sarah, a PhD candidate in biological sciences, tips her hand with the title: Obesity – How the Media Misleads You.

In the original study (actually a meta-analysis of previous studies), the authors calculated the “relative risk” of dying for various populations. Here is what Sarah discovered in the full study, ranked in order of risk:

Metabolically healthy, normal weight 1
Metabolically healthy, overweight 1.21 (0.91 – 1.61)
Metabolically healthy, obese 1.24 (1.02 – 1.55)
Metabolically unhealthy, obese 2.65 (2.18 – 3.12)
Metabolically unhealthy, overweight 2.70 (2.08 – 3.30)
Metabolically unhealthy, normal weight    3.14 (2.36 – 3.93)

Look at the folks at most risk!

Now, it’s possible that the confounds are things like eating disorders, smoking, and other negative health behaviors. And Dr. Sharma’s work suggests that the number of metabolically healthy and obese is not particularly high, perhaps 10-15%. But what we don’t really know, largely because of the cultural acceptance that obesity is the only marker for health, is how many metabolically unhealthy, normal weight people there are.

So what?

Interestingly, there’s a curious post over on Yoni Freedhoff’s site about one person’s bad experience with HAES. But I think commenter valerie nails it (emphasis mine):

Maybe I am a bit slow, but I thought HAES was about adopting health-promoting behaviors. Regardless of your weight. Is it not?

Those health-promoting behaviors might include avoiding junk food, being active and getting enough sleep, or they might focus on drinking in moderation, not smoking and buckling your seatbelt. Regardless of your weight.

If you chose to change your weight for medical reason, well, good luck. You don’t control your weight. You control your behaviors. The behaviors you chose to adopt might have an impact on your weight, but they might not.

I am not a HAES evangelist, but I do think that their focus on healthy behaviors rather than weight loss is hard to argue with.

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Obesity and poverty

Something that is making the round of the media lately is the findings of a December 2010 CDC report, Obesity and Socioeconomic Status in Adults: United States, 2005–2008 (PDF). The CDC looked at survey data from their National Health and Nutrition Examination Survey (NHANES) and found that the link between obesity and poverty was hardly clear-cut:

income

For more details, check out the report or other media takes (The Atlantic, Pew, and ConscienHealth).

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Stanton Peele, the psychotherapist who often writes about the flaws in the “addiction as disease” model, posted an interesting article for Psychology Today titled Unbelievable Things About Quitting Addictions. His chief unbelievable thing? That ‘heavily’ addicted people (e.g., drug addicts) often quit addictions more readily than ‘less’ addicted ones (e.g., alcoholics).

His conclusion (emphasis mine):

Forget everything you have learned about the disease of addiction. Then, and only then, can you begin to understand it. The most important thing Heyman found in remission is values, and being in a place in life where you can express and sustain them … And why do drug addicts quit more readily than smokers and drinkers? Because—as Charles Winick pointed out in “Maturing Out of Narcotic Addiction” in 1962—maintaining a drug addict career is too arduous.

As the quote suggests, Peele bases this in part on Heyman’s analysis earlier this year of “four major national US surveys of psychiatric disorders and problems related to substance use.” Heyman’s main findings:

  • addiction is generally not ‘chronic’
  • probability of remission the same each year of dependence
  • treatment generally not needed
  • dependence on legal drugs lasts longer

I’ll grant this model of addiction is controversial, but I find the concept that dependence on legal drugs (like alcohol and cigarettes) is more difficult very interesting. It reminds me of something I wrote years ago about a potential link between our diet and the endocannabinoid system: that the effect (of anandamide, THC’s natural relative) isn’t as strong (reduced potency) but it lasts and lasts and lasts.

Seems to me that it would be quite easy to maintain a career as someone with a dependence — or addiction — to food. And perhaps that contributes to what may make quitting that much harder.

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Annoyed woman So I’ll bet you heard the news. A professor and some of his students found that Oreos are “just as addictive as cocaine” in rats.

Why is this annoying? For one, it’s not particularly innovative … research like this has been done (and done better) years ago.

For another, it’s misleading. As Emily Deans pointed out yesterday on Twitter:

just because a substance hits the pleasure centers doesn’t mean ‘as addictive as cocaine.’

Or as Yoni Freedhoff pointed out on his blog this morning:

Putting aside any concerns with experimental methodologies, if our pleasures centres didn’t light up like Christmas trees when faced with sugars and fats then I’m pretty sure there wouldn’t be over 7 billion of us walking the planet, because up until only about a millisecond or so in the grand scheme of time, those who were more driven to eat were the only ones who survived.

Understanding our brain’s reward system is important, but it’s also important not to overstate the case and, like some, conflate normal behavior with addiction.

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In Beyond the Paleolithic prescription: incorporating diversity and flexibility in the study of human diet evolution (free full text), anthropology researchers Bethany Turner and Amanda Thompson take an interesting and expanded look at what they see as the limitations in much of the current discussions of the so-called paleo diet.

One section I particularly liked was their “Rethinking the human sweet tooth” in the potential nutritional interventions section:

The assumption that humans evolved an affinity for sweet and fatty tastes that is highly adaptive but mismatched to modern contexts might reasonably lead one to conclude that unchecked consumption of sugary and high-fat foods is something of an inevitability. A wider perspective, however, focuses on the mechanisms of an affinity for sweet and fatty tastes rather than ending the explanation with a discordant adaptation. Humans learn to like sugar along with a host of other flavors in utero; moreover, sugars are associated with the secretion of endogenous opiates that confer pleasurable sensations and activate reward pathways in the brain. Similarly, the consumption of fatty foods stimulates the production of endogenous cannabinoids that create comparable reward effects. In modern environments characterized by cheap, readily available sugary and fatty foods and psychosocial stress that is both uniquely human and differentially endured, an unchecked consumption of sugars and high-fat foods could more reasonably reflect socially learned and socially reinforced behaviors than an adaptation gone awry.

Intervention strategies based on this broader perspective would not assume that removal of sugars, other simple carbohydrates, and excessive saturated fats from the diet is necessary because they trigger a mismatch born of adaptation. Instead, interventions could focus on manipulating the intrauterine flavorscape or early-life diets to impart an affinity to a broader range of taste stimuli unrelated to sweet tastes. Plant-based spices and aromatics can play a significant role in forming positive associations with foods based on flavor and olfactory properties. Since these associations are unrelated to fat or caloric content, such spices and aromatics could therefore become useful tools in shaping children’s preferences for plant-rich diets. Importantly, interventions aimed at preventing metabolic diseases could also benefit from focusing as strongly on reducing sources of psychosocial stress as on controlling food intake.

It’s an academic read, but it’s largely a review of existing literature and well worth your time. Some people may think that paleo has jumped the shark, but I think there is a great future in understanding how evolution shapes our interaction with our current environment. I’m happy that researchers like Turner and Thompson are expanding the discussion.

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Annoyed woman Orexigen, maker of the potential obesity drug Contrave (a combo of naltrexone and bupropion) has recently published the results of their phase III trial (PDF).

This is the trial that was requested by the FDA in early 2011 after the phase II study was completed. The goal of the new trial was to “demonstrate that the risk of major adverse cardiovascular events in overweight and obese subjects treated with naltrexone/bupropion does not adversely affect the drug’s benefit-risk profile.”

Yes, it’s kinda important that an obesity drug not have adverse affects … remember fen-phen? It was relatively popular until the reports of potentially fatal “pulmonary hypertension and heart-valve abnormalities” started showing up.

It’s been more than a decade since the media and researchers wrote about fen-phen with the headline “dying to be thin” so it’s understandable that this time the FDA is being uber-careful about the next generation of obesity drug.

So what does the new study tell us?

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