Thursday, January 31, 2013

The New England Journal's Obesity Mythbusting


Yesterday an article authored by a veritable who's who list of obesity researchers was published in the New England Journal of Medicine. Titled, "Myths, Presumptions, and Facts About Obesity", it details what the authors describe as seven popular obesity related "myths", six common "presumptions", and nine understated evidence supported "facts".

While I agree almost wholeheartedly with the "Facts" section, and agree too that the "Presumptions" (presumptive in that we don't have enough data yet to decide one way or the other if they're true) are indeed still presumptions, I'd argue some of the "Myths" have yet to be busted.

For what they're worth, here are the myths, presumptions and facts and my thoughts occasionally interspersed therein.

The Myths

These are subjects that the authors feel have sufficient data to conclusively dismiss them as false. While I agree in some cases, I don't in all. That doesn't necessarily mean the authors are wrong and that I'm right, just that our opinions differ:

1. "Small sustained changes in energy intake or expenditure will produce large, long-term weight changes".

(Agree this is a myth. Putting this another way, I'll often tell my patients weight loss is insert-adjective here. Meaning small changes only lead to small losses and if you want to lose a huge amount of weight, you'll need to undertake (and sustain) a huge amount of change.)

2. "Setting realistic goals for weight loss is important, because otherwise patients will become frustrated and quit".

(Disagree. Not that the statement's true or false, just that the authors call it a myth consequent to the fact that there isn't robust evidence proving it to be true or false. Until there's robust evidence one way or the other, tough to call this one a myth and I'd have put it into their "presumptions" section. Moreover, tough to apply to everyone as no doubt some people likely respond wonderfully to aggressive goals, while others quit consequent to not reaching a dream destination.)

3. "Large, rapid weight loss is associated with poorer long-term weight-loss outcomes as compared with slow, gradual loss".

(Disagree. Here again is an area where I don't think we have sufficient data. The authors refer to year-long studies as long term data and frankly I don't think that's long term. For instance if a person rapidly loses 80lbs during an 8 month meal-replaced, very-low-calorie-diet looking at 1 year as "long term" only gives that person 4 months to regain. So I'd argue anything less than 2 year data is a short-term outcome and that we need data from at least 2 or more years out to draw long term conclusions and that's truly rare to come by.)

4. "It is important to assess the stage of change or diet readiness in order to help patients who request weight-loss treatment"

(Disagree. Here the authors report that studies that have looked at stage of change in people voluntarily entering weight loss programs didn't predict outcomes. Yet as the authors themselves point out, by definition folks voluntarily choosing to enter weight loss programs are at least minimally ready to face change. But for the clinician working their primary practice and not a practice like mine for instance, no doubt stage of change assessment crucial - if not for success than certainly for a respectful doctor patient relationship.)

5. "Physical-education classes in their current form, play an important role in reducing or preventing childhood obesity"

(Here all I can say is AMEN. No doubt evidence very clearly suggests kids aren't going to burn off or prevent obesity by means of school based PE classes.)

6. "Breast-feeding is protective against obesity"

(The authors report that a WHO meta-analysis on the subject was flawed, and that well controlled trials failed to demonstrate any clear benefit to breastfeeding on reducing obesity risk.)

7. "A bout of sexual activity burns 100 to 300 kcal for each participant"

(By their calculations the authors predict the average act of intercourse burns in the neighbourhood of 14 calories (sorry folks).)

The Presumptions 

These are subjects that as yet remain unproven one way or the other.

1. "Regularly eating breakfast is protective against obesity"

(Agree that it's not true for everyone. But perhaps important to note that the National Weight Loss Registry reports 78% of successful maintainers regularly eat breakfast. The flip side of that is that 22% don't. As I've blogged about (yesterday in fact), different strokes for different folks, though I'd argue (as would the Registry) that for most, breakfast may be important.)

2. "Early childhood is the period in which we learn exercise and eating habits that influence our weight throughout life"

3. "Eating more fruits and vegetables will result in weight loss, or less weight gain, regardless of whether any other changes to one's behavior or environment are made"

4. "Weight cycling is associated with increased mortality.."

5. "Snacking contributes to weight gain and obesity."

(Depends wholly on the snacks!)

6. "The built environment, in terms of sidewalk and park availability, influences obesity."

The Facts

These are the nine points the authors feel there's sufficient evidence to be true.

1. "Although genetic factors play a large role, heritability is not destiny"

2. "Diets (reduced energy intake) very effectively reduce weight, but trying to go on a diet or recommending that someone go on a diet generally does not work well in the long term."

3. "Regardless of body weight or weight loss, an increased level of exercise increases health."

4. "Physical activity or exercise in a sufficient dose aids in long term weight maintenance."

5. "Continuation of conditions that promote weight loss promotes maintenance of lower weight."

(Meaning whatever you do to lose it, if you want it to stay off, you need to keep doing it)

6. "For overweight children, programs that involve the parents and the home setting promote greater weight loss or maintenance."

7. "Provision of meals and use of meal-replacement products promote greater weight loss."

(The inclusion of this "fact" confused me consequent to point number 5! If you lose weight utilizing meal replacements and you stop using meal replacements, the weight lost as a consequence of their use may well return. What percentage of folks in meal replacement based programs are counselled or are prepared to live with meal replacements for life?)

8. "Some pharmaceutical agents can help patients achieve clinically meaningful weight loss and maintain the reduction as long as the agents continue to be used."

9. "In appropriate patients bariatric surgery results in long-term weight loss and reductions in the rate of incident diabetes and mortality."

Bookmark and Share

12 comments:

  1. This was such an interesting article. I'm glad to have an MD "decipher" the scientific language into layman terms.

    ReplyDelete
  2. Sharon10:16 am

    " While I agree in some cases, I don't in all. That doesn't necessarily mean the authors are wrong and that I'm right, just that our opinions differ"
    Aaahhh......the sound of civil discourse on a difficult topic. Yes.

    ReplyDelete
  3. Anonymous2:18 pm

    OMG, just look at the funding these "scientists" have received from Big Food! scroll down to the bottom of the page http://www.nejm.org/doi/full/10.1056/NEJMsa1208051

    ReplyDelete
    Replies
    1. I'll paste it here to save the trouble of visiting the link:

      The views expressed in this article are those of the authors and do not necessarily represent the official views of the National Institutes of Health.
      Supported in part by a grant (P30DK056336) from the National Institutes of Health.
      Dr. Astrup reports receiving payment for board membership from the Global Dairy Platform, Kraft Foods, Knowledge Institute for Beer, McDonald's Global Advisory Council, Arena Pharmaceuticals, Basic Research, Novo Nordisk, Pathway Genomics, Jenny Craig, and Vivus; receiving lecture fees from the Global Dairy Platform, Novo Nordisk, Danish Brewers Association, GlaxoSmithKline, Danish Dairy Association, International Dairy Foundation, European Dairy Foundation, and AstraZeneca; owning stock in Mobile Fitness; holding patents regarding the use of flaxseed mucilage or its active component for suppression of hunger and reduction of prospective consumption (patents EP1744772, WO2009033483-A1, EP2190303-A1, US2010261661-A1, and priority applications DK001319, DK001320, S971798P, and US971827P); holding patents regarding the use of an alginate for the preparation of an aqueous dietary product for the treatment or prevention of overweight and obesity (patent WO2011063809-A1 and priority application DK070227); and holding a patent regarding a method for regulating energy balance for body-weight management (patent WO2007062663-A1 and priority application DK001710). Drs. Brown and Bohan Brown report receiving grant support from the Coca-Cola Foundation through their institution. Dr. Mehta reports receiving grant support from Kraft Foods. Dr. Newby reports receiving grant support from General Mills Bell Institute of Health and Nutrition. Dr. Pate reports receiving consulting fees from Kraft Foods. Dr. Rolls reports having a licensing agreement for the Volumetrics trademark with Jenny Craig. Dr. Thomas reports receiving consulting fees from Jenny Craig. Dr. Allison reports serving as an unpaid board member for the International Life Sciences Institute of North America; receiving payment for board membership from Kraft Foods; receiving consulting fees from Vivus, Ulmer and Berne, Paul, Weiss, Rifkind, Wharton, Garrison, Chandler Chicco, Arena Pharmaceuticals, Pfizer, National Cattlemen's Association, Mead Johnson Nutrition, Frontiers Foundation, Orexigen Therapeutics, and Jason Pharmaceuticals; receiving lecture fees from Porter Novelli and the Almond Board of California; receiving payment for manuscript preparation from Vivus; receiving travel reimbursement from International Life Sciences Institute of North America; receiving other support from the United Soybean Board and the Northarvest Bean Growers Association; receiving grant support through his institution from Wrigley, Kraft Foods, Coca-Cola, Vivus, Jason Pharmaceuticals, Aetna Foundation, and McNeil Nutritionals; and receiving other funding through his institution from the Coca-Cola Foundation, Coca-Cola, PepsiCo, Red Bull, World Sugar Research Organisation, Archer Daniels Midland, Mars, Eli Lilly and Company, and Merck. No other potential conflict of interest relevant to this article was reported.
      Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

      Delete
  4. Carrie3:02 pm

    I was curious as to why you didn't mention the financial ties the researchers have to the food/beverage/diet industry as well. What is your opinion - should this impact how credible we interpret the study as being?

    ReplyDelete
    Replies
    1. Truthfully didn't look when I read the piece. As far as whether or not it should skew interpretation - only thing to also note is that it's tough to find folks without conflicts who are also world renowned experts as those are the folks whose opinions are sought out and paid for.

      Delete
    2. Anonymous11:13 am

      That is a very sad comment on science today, if it is that "tough to find folks without conflicts" of interest. What about funding from NIH or other public health sources? I'm afraid that I can't take research about obesity that is funded by Kraft and Coca-Cola very seriously. Don't these "world renowned experts" have any idea how it devalues their "sought after opinions" if they are also "paid for" by the industry?
      PS am not trying to stay anonymous, just don't know how to post comments with one of those profiles.
      Helen

      Delete
  5. Excellent evaluation, Sari. I'm sending your article to my Facebook followers.

    ReplyDelete
  6. I've been arguing against "small changes" for a long time! "Small changes" is a term used in the media to create positive, engaging content. Used with the same intention as expressions like "everything in moderation," it's what people want to hear. They want to be told they can get big results with little effort and little sacrifice. An audience won't have a positive opinion of a talk show host who tells them they're going to have to work their butts off to get results.

    ReplyDelete
  7. Anonymous8:37 pm

    I'm not sure I agree with the "small changes" one. Yes, a small change on its own will not have huge consequences. But you can make a small change now. And then another, when the first one is habit. And then another. And eventually, you've changed quite a bit, but only in small increments. It's when I try to change my life radically all at once that I fail, because it's too hard to keep up.

    That may not be precisely what the point addresses -- burning an extra hundred calories a day certainly won't produce infinite weight loss over time. But I hate to see articles discouraging incremental changes.

    ReplyDelete
  8. I did NOT know that there was a "Knowledge Institute for Beer"

    Always assumed that was a campus Frat....wonder if it's too late to do a residency there ;-)

    ReplyDelete
  9. Pardon the bump, but this topic has come up in a twitter exchange.
    "...small changes only lead to small losses and if you want to lose a huge amount of weight, you'll need to undertake (and sustain) a huge amount of change."
    What about: "A series of small sustained changes in energy balance will produce large, long-term weight changes.

    Little changes, big results."?

    ReplyDelete