Exercise and Weight Loss – A Primer

Today we have another excellent guest post from PhD Candidate Martin Sénéchal describing Dr Bob Ross’ presentation on exercise and weight loss from the recent Canadian National Obesity Summit.  I’ve included Martin’s post immediately below, followed by a short summary and some of my thoughts for those unable to enjoy Martin’s post in French.

Here is Martin:

Perte de poids ou exercice? Probablement pas les deux!

Lors de la dernière journée du « 2nd Canadian Obesity Summit », la session intitulée : «Physical Activity for Canadians: New Science, New Guidelines, New Approaches » a capté mon attention. Chacune des présentations avait un message clé, mais celui qui m’a  particulièrement marqué est le message du Dr. Ross, professeur à Queen’s UniversityIl a fait la preuve claire qu’une perte de poids grâce à l’exercice seul est atteignable (Ross et al., 2000Ross et al., 2004) à plus ou moins court terme, et ce, lorsque les participants sont supervisés de façon optimale par des professionnels. Néanmoins, on parle d’une très grande quantité d’exercice et d’une supervision intensive.

Cependant, le problème c’est que dans un environnement ‘obésogénique’ et lorsque qu’il n’y a pas de supervision ou d’encadrement, il est très difficile de perde du poids à court et long terme par l’exercice seul. C’est peut-être la raison qui permet d’expliquer pourquoi les gens qui font de l’exercice en salle de conditionnement n’arrivent pas toujours à atteindre leurs objectifs de perte de poids. C’est-à-dire qu’ils ont de la difficulté à reproduire ce qui est observé en laboratoire.

Néanmoins, l’exercice semble être efficace pour maintenir la perte de poids, à long terme. Pour y arriver, on parle d’un minimum de 250 minutes d’exercice par semaine ce qui demande une certaine rigueur. Cependant, Dr. Ross mentionne que l’absence de perte de poids ne doit absolument pas être vue comme un échec. Au contraire, le fait d’avoir changé un comportement telle la pratique d’activité physique devrait être vu comme une victoire. En effet, ce qu’on doit viser avant tout, c’est le changement de comportement (la pratique régulière d’activité physique) et non le résultat (l’obésité). De plus, le Dr. Ross précise que même s’il y a absence de perte de poids, le tour de taille et le tissu adipeux viscéral sont souvent réduits grâce à l’exercice et la capacité aérobique augmentée.

En somme, l’exercice procure de nombreux avantages et ce, malgré l’absence de perte de poids.

Alors, à vos souliers et bougez!

Martin Sénéchal


Ross, R., Dagnone, D., Jones, P. J., Smith, H., Paddags, A., Hudson, R., et al. (2000). Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial. Ann Intern Med, 133(2), 92-103.

Ross, R., Janssen, I., Dawson, J., Kungl, A. M., Kuk, J. L., Wong, S. L., et al. (2004). Exercise-induced reduction in obesity and insulin resistance in women: a randomized controlled trial. Obes Res, 12(5), 789-798.

Travis’ Thoughts & Summary:

In his talk Dr Ross described how exercise  (with or without a reduced calorie diet) can produce dramatic weight loss in tightly controlled laboratory studies, as he himself has shown in numerous papers.  And yet exercise alone is typically insufficient for promoting lasting weight loss in the real world.  In this way exercise is very efficacious at reducing body weight (e.g. it works very well in a best case scenario when all variables can be tightly controlled), however it is not particularly effective (e.g. it doesn’t work so well in the real world).

As always, Dr Ross was also quick to point out that simply because exercise may not reduce an individual’s body weight does not mean exercise isn’t worth the effort – exercise has a number of important health benefits regardless of what is happening to body weight. For this reason it is likely better for people to focus on healthy behaviours like increasing physical activity and eating a healthy diet, rather than focusing on a less controllable endpoint like body weight.

No doubt that Dr Ross will be expanding on all of these issues in the Forks vs Feet debate tomorrow (May 12) at noon EST at the University of Ottawa Health Sciences Campus (sandwiched between CHEO and the General Hospital).  The debate is free, as are refreshments, and if you are in the Ottawa area I would highly recommend that you come check it out.  For those unable to make it to the event live we will also be live-streaming the event here at Obesity Panacea – just click play on the video player embedded below (email subscribers can view the player by visiting our website here).

Watch live video from travissaunders on Justin.tv


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3 Responses to Exercise and Weight Loss – A Primer

  1. I think the key is to disconnect the link between exercise and calories. Exercise in support of calories in/calories out is to me, far less useful than exercise in support of successful weight loss through other means.

    For example, I’ve been following essentially a primal diet (paleo+dairy) for the last 6 months, but as healthy as my diet’s been, my last fasting insulin was 12 … not where I want it to be for either health or weight loss.

    So I have gotten started with Body By Science workouts. This is a high intensity strength program that probably barely makes a dent in my caloric expenditure for the day, but I’m betting it will make a big difference over time in terms of adding muscle and restoring insulin sensitivity. We’ll see!

  2. WRG says:


    How can we help the population to actually improve its health? Perhaps we should start by decoupling weight loss from health gain. Although this seems counter-intuitive to the general public and it’s certainly anathema to the media, which won’t increase its advertising dollars with headlines like “Moderate exercise and a well-balanced diet won’t help you lose weight! But you’ll be a lot healthier!”, this is precisely the message that the world needs to hear.

    Right now, I think we’re fighting a losing battle. The witch-hunt against overweight is, if anything, picking up steam and children have become the new battleground. Nevertheless, I do appreciate your thoughtful articles and encourage you and your colleagues to keep thinking outside the box and remaining open to new paradigms.

  3. Pingback: Perfect Health Diet » Around the Web; Morgellons Edition