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Exercise won't make you thin, or so concludes misguided TIME magazine article

Monday, August 17, 2009 Posted by Peter Janiszewski, PhD

If you haven’t heard about it yet, you are in the minority.

The news, blogosphere, academic associations, etc. have been abuzz (rather negatively) regarding a recent cover page story in Time magazine entitled, “Why Exercise Won’t Make You Thin.”

In the story, John Cloud selectively chooses to report singular studies, often incorrectly, misquotes experts, often showcasing his naive understanding of physiology, all in order to arrive at his apparently preconceived (and largely absurd) notion that not only will exercise not help you lose weight – it may actually make you fatter.

In the first page of the article, he asks the question: “Could exercise actually be keeping me from losing weight?”

Throughout the article, Cloud painfully describes with very apparent distaste his “grueling” 4 hours of weekly exercise in a manner that is reminiscent of many infomercials which also attempt to convince the viewer that exercise is too difficult and should be replaced by whatever product being peddled (see the Slender Shaper video for a great example of “painful situps”). The interesting thing about his confessions is that only approximately 90 minutes of his weekly exercise is actually composed of aerobic activity – the very activity you should be doing if your goal is to expend calories.

In contrast, how much exercise do major medical authorities suggest for weight-loss?
Answer: 60-90 minutes of aerobic-type activity on MOST DAYS OF THE WEEK!

Not on one day of the week, as the author is performing.

Throughout the article you get the impression that while he demonizes exercise as the cause of his apparent inability to shed pounds, the likely cause of his issues is his improper nutritional habits. For example, he admits to previously “self-medicating with lots of Italian desserts”. He also describes craving French fries or greasy bourritos after exercising – not sure how common that is…

It should come as no surprise that nutrition is extremely important when it comes to weight management. You can’t expend 300 calories on a jog, follow it up with a 500 kcal bourrito and expect to lose weight. Additionally, when attempting to create a negative energy balance to shed pounds – it is pragmatically easier to restrict food intake than to burn the same number of calories through exercise. Thus, calorie restriction and proper nutrition (taking into account meal frequency, macronutrient composition, etc.) is a critical component of a lifestyle based approach to dealing with excess weight.

However, to suggest that: “Exercise… isn’t necessarily helping us lose weight. It may even be making it harder” is simply incorrect and given the popularity of the publication in which this is written, largely irresponsible from a public health perspective.

Back in the early 1990’s, the popular notion was that exercise interventions are not as efficacious in reducing body weight or fat mass as are dietary ones. Unfortunately, these conclusions developed predominantly from a rather unfair comparison of studies: as an example, comparing weight loss of a dietary intervention reducing daily caloric intake by 700kcal versus an exercise intervention which increases energy expenditure by 300kcal per day. You can well guess who the winner was…

However, in a 2000 study from our lab publiched in the Annals of Internal Medicine, we directly compared the efficacy of diet versus exercise to reduce weight, fat mass, etc. in a group of men after controlling for the caloric deficit created (fair comparison). In that study, over the 3 month intervention, individuals lost about 7-8kg, regardless of the intervention (diet or exercise). Our lab then replicated this study in women and showed much the same results: when carefully controlling for the number of calories – diet and exercise produce the same degree of weight loss. Additionally, from these studies it is also apparent that exercise will result in meaningful weight loss – WHEN it is done in appropriate volume.

Of course, the obvious caveat here is that it is much easier to reduce caloric intake by 1000 kcal than to expend that much via physical activity. Thus, for practical reasons, diet is the cornerstone of weight management.

More important than any this is the following:

Regular physical activity is good for your health and reducing basically any disease outcome (diabetes, cardiovascular disease, cancer, erectile dysfunction, depression, anxiety, etc.) INDEPENDENT of its effect on body weight.

As I have written in published review papers, and have discussed previously on Obesity Panacea, the focus on weight as the primary outcome in lifestyle based obesity interventions is myopic and misguided – and this is really where the author of the TIME article fails. Individuals of all sizes, and ages, can vastly improve their health without a noticeable budge in their scale weight. Thus, true treatment benefit (on lipids, insulin sensitivity, BP, etc.) may be masked by an apparent resistance to weight-loss. This lack of weight change will likely be interpreted by the individual as a treatment failure causing them to discontinue the healthy behaviors.

Unfortunately, this is EXACTLY the conclusion Mr. Cloud comes to at the end of the article, and it is this conclusion that I believe to be the most damaging.

In the last sentence of the article, Cloud sums up by stating that “tomorrow I might skip the VersaClimber…” I truly hope others do not follow TIME’s misguided advice.

While there is much more that I could discuss in regards to this article, I should also point our readers to other sources of disagreement over the contents of the TIME article – some of them, from the very people who were misquoted in the article itself.

For example, the American College of Sports Medicine released a statement disagreeing with the conclusions reached by Cloud in the recent article.

In that statement, Dr. John Jakicic, states: “The statement ‘in general, for weight loss, exercise is pretty useless’ is not supported by the scientific evidence when there is adherence to a sufficient dose of physical activity in overweight and obese adults.”

“Again, it is clear in this regard that physical activity is one of the most important behavioral factors in enhancing weight loss maintenance and improving long-term weight loss outcomes,” Jakicic is also quoted as stating in the statement.

What’s worse, Dr. Tim Church, a colleague of both Travis and I, and someone whom I have gotten to know personally over the years, has come out and said that Mr. Cloud has actually misrepresented his professional opinions in the article. This is rather unfortunate for Mr. Cloud, as much of his thesis rests on the results of a recent study by Dr. Church and his erroneous extrapolations thereof.

I feel there is more backlash to come over the next little while (letters to the editor are a certainty) – I will keep you all updated.

I assure you that I will be writing a letter to TIME magazine scorning them on the rather biased and poorly researched article.

Don’t believe everything you read…


Peter


UPDATE: Click here to read my column on the TIME story published in the Kingston Whig Standard, Saturday August 22, 2009.


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Ross R, Dagnone D, Jones PJ, Smith H, Paddags A, Hudson R, & Janssen I (2000). Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial. Annals of internal medicine, 133 (2), 92-103 PMID: 10896648

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11 Response to "Exercise won't make you thin, or so concludes misguided TIME magazine article"

  1. Matt Said,

    I don't need to look at the evidence to show me the TIME article is accurate. I mean, when I work out regularly I feel hungrier. When I am hungrier I eat more. Therefore exercise makes me fat. Pretty obvious to me. I also enjoy the author's previous health related articles, such as "The Smoking Diet - Ditch the snacks and take a drag!" where he explains the weight loss effects of smoking, and my favorite, "Watching Scary Movies - more effective than running" as he shows us the elevation in heart rate during the scary scenes is similar to when he runs, therefore the same. Why waste time looking through studies when this guy lays it out there for you. Sorry Peter, I disagree with you on this one. Yet another example where common sense supercedes evidence!

    Posted on August 17, 2009 at 11:20 PM

     
  2. Richard Eis Said,

    My god I hope that was sarcasm.

    Posted on August 18, 2009 at 3:32 AM

     
  3. Chris Said,

    when there is adherence to a sufficient dose of physical activity in overweight and obese adults

    I think this is the key statement. Mr. Cloud's point is that "sufficient dose" can only be defined in relation to a host of other factors like consumption. If you run for a couple hours and then have an ice cream sunday, you might not have exercised with a "sufficient dose."

    I personally have not experienced the hunger outcomes from exercise. I do usually feel thirsty, however, and I have noted in myself that I sometimes confuse thirst cravings and sugar cravings. My guess is that this water/sugar mix up happens in some people while others are already looking for an excuse to eat a sugary dessert before they even go to the gym.

    Posted on August 18, 2009 at 4:38 PM

     
  4. Peter Janiszewski, PhD (Cand.), MSc Said,

    Richard, I have sneaking suspicion I know exactly who "Matt" is and I can almost certainly guarantee his comment was written with a heavy dose of sarcasm.

    Thanks Matt - I had a good laugh!:) "Common sense supercedes evidence" - I may use that line in the future.

    Peter

    Posted on August 18, 2009 at 9:50 PM

     
  5. Alberto Said,

    Thanks for posting this one. I think a great problem with many people is that they think: I exercised, this means I can eat what I want (without feeling guilty). Physical activity should be separated from eating "disorders".

    Posted on August 19, 2009 at 4:24 AM

     
  6. Alan Millar Said,

    A journalist writes a misleading article, misrepresenting scientific knowledge. Dangerous.

    Scientists write letters correcting the article. Problem solved. I don't think so.

    Time should be pressured to publish a rebuttal by someone skilled both in science, and just as importantly, rhetoric.

    Magazines just love being able to provide "balanced" coverage - in which science is mangled in a way that similar abuse of reporting in a legal trial, for example, would seriously discredit the publication.

    It's time to fight back and put science reporting on the same level as political and legal reporting - out of the realms of opinion-based, "life-style" reporting.

    Posted on August 19, 2009 at 5:22 AM

     
  7. Jan Said,

    Exercise will help you loose wait in theory or in really controlled situations. This however has nothing to do with the real world, where things are theoretical nor controlled.

    In the real world:
    A healthy body can loose weight the most efficient and practical by reducing calorie intake. Excercise is will get you healthy, therefor exercise is a part of the equation, but (in practical sense) not part of the negative energybalance theory.

    How is that for a compromise.
    Jan

    Posted on August 19, 2009 at 12:12 PM

     
  8. Peter Janiszewski, PhD (Cand.), MSc Said,

    @ Jan - What you describe is really a re-hashing of Cloud's thesis.

    "exercise is a part of the equation, but (in practical sense) not part of the negative energybalance theory"

    Not sure what meaning was intended with that statement, but to suggest that if someone jogs for 60 minutes on most days and expends 500kcal each time, that this would somehow not create or contribute to a negative energy balance is simply incorrect.

    Yes, nutrition needs to be part of the picture, and this is where I think Cloud fails miserably. As I explained you can not perform a low dose of activity and reward yourself with double the caloric value as that expended during the activity, and expend to lose weight.

    BUT - if you maintained your current diet (no decrease or for that matter increase in caloric intake) and exercised at an appropriate volume (60-90 mins most days) you would absolutely lose weight - to suggest otherwise would violate the basics of energy conservation.

    Peter

    Posted on August 19, 2009 at 1:35 PM

     
  9. Jan Said,

    Peter,

    I'm convinced you're right, but besides the obvious research which is clear on this point, there is a practical point to it.

    I've overseen nationwide multicenter programs in the Netherlands with thousands of people and have personal experience in helping hundreds of people loosing weight en staying slim in and out of fitness centers. Besides having a MsC in nutrition, health sciences and psychology, I spent 2 hours a day reading up research (on health, not just weightloss) and 20 hours a week clinic duty, besides teaching healthsciences.

    I'm a pragmatic person on par with science. But if we want to help people, we need to understand for example the Hawthorn effect and that means that people being observed will respond differently (like in a controlled experiment). I combined the scientific knowledge with my clinical experience, which is not a controlled experiment but more like a thousandfold casereport.

    If you focus on exercise as a health benefit and nutrition as a way to loose weight. Things get much simpler. As soon as you start telling people that they ate the candybar and it doesn't matter, but they have to walk 30 minutes longer. Things start getting confusing.

    Also very discouraging is the fact that some people are in the gym 4 times a week and don't loose weight. Of course they eat to much, but there is no real world reference for the energy balance. They understand the rationale, but will reject it emotionally.

    So, having said this. You're right, but to be honest it's a academic discussion. If you want to help people, physiology is not enough. Knowing how people perceive thing, how they learn and how they embed behavior is in my opinion at least as interesting as a part of the equation. Wouldn't you agree?

    Posted on August 19, 2009 at 3:53 PM

     
  10. bcoppola Said,

    I too read the Time article with some bemusement; but as a layperson I gave it the benefit of the doubt as it seemed somewhat plausible. But still the BS radar kept twinging.

    My favorite CV exercise is bicycling and I do indeed feel hungrier sometimes after a hard ride. OTOH, sometimes I have simply "rewarded" myself, hungry or not, with a high calorie indulgence (ice cream is my weakness).

    Still, it has taken very little willpower to simply reduce the frequency of those "rewards" and my midsection fat has diminished. And post ride hunger is mitigated or eliminated by making sure I'm well fueled before.

    As noted, my scale weight has changed little (~5 lbs or so) but my trousers fit much better. So where's the weight coming from? Probably increased muscle. Good tradeoff IMO.

    Also, I take in stride speeds and distances that would have been unthinkable a few years ago. And I'm in my mid 50s.

    Now I need to get better at keeping up my weight/core exercises.

    Found my way here via a link on Science Blogs. I'll share this article with my bike club.

    Posted on August 28, 2009 at 1:22 PM

     
  11. Peter Janiszewski, PhD (Cand.), MSc Said,

    @ bcoppola

    Thanks for your comments and for spreading the news.

    You may be interested in reading a prior post I had on the notion of physical activity affecting health and body composition despite no change in scale weight. Click this link to read more: http://www.obesitypanacea.com/2009/01/physical-activity-in-treatment-of.html

    Posted on August 28, 2009 at 2:12 PM

     

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We are PhD students in the School of Kinesiology and Health Studies at Queen's University in Kingston, Ontario. Our research focuses on the relationships between obesity, physical activity, and health risk. This blog is our attempt to consider the many "cures" for obesity that we read about on a daily basis. Enjoy.

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The opinions expressed here belong only to Peter and Travis and do not reflect the views of any organization. Any medical discussion on this page is intended to be of a general nature only. This page is not designed to give specific medical advice. If you have a medical problem you should consult your own physician for advice specific to your own situation.

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