Canadian Blogs



You Almost Certainly Don’t Need to Replenish Your Electrolytes

Posted May 20, 2015 by Yoni Freedhoff

The sport drink industry is a massive one. Estimated at nearly $7 billion in 2012 (and it was growing), the industry preys in part on the notion that because our sweat is salty, we need to replace it, and to replace it quickly.

But do we?

A study published way back in 1991 tried to answer that question.

The researchers took 8 cyclists and ran them through 6 gruelling hours of intermittent cycling in an 86°F room of 50% humidity, and kept their intensities at 55% of their VO2 Max. Each cyclist repeated this exercise 3 times on 3 separate occasions and 3 separate conditions. Once with no water or sports drink, the next time with just water, and lastly with just a sports drink where in both the water and sports drink treatments both were provided in quantities sufficient to replenish their volume of losses to sweat. The cyclists would cycle for 13 minutes, and then take a 2 minute break during which their heart rate, rectal temperature, and their perceived exertion were measured. Blood was drawn at the 15 minute mark and at hours 2, 3, 4, 5, and 6 to measure plasma sodium and plasma aldosterone.

The results were striking and easy to describe.

Simply put, if the study is to be believed:

1. You don’t need to hydrate yourself at all during non-dramatic bouts of exercise. Certainly if you’re thirsty, that’s your sign to drink, but if you’re not thirsty, probably no need. In this experiment’s case, when drinking nothing, these cyclists DID have to stop the experiment short, but only after a long 4.5 hours of cycling (where the experiment was stopped short due to a marked rise in core temperature, heart rate and perceived exertion).

2. Unless you’re exercising vigorously for longer than 6 hours straight, you don’t need a sport drink to replenish your “electrolytes“, because in this study, there was no difference in plasma sodium levels between the water drinkers and the electrolyte drinkers even after 6 hours of heavy-duty exercise!

I asked my friend Alex Hutchinson, author of the fantastic Which Came First Cardio or Weights his thoughts on the matter and he put it rather succinctly,

electrolytes are irrelevant in the vast majority of situations“.

So definitely don’t ignore your body’s cues and do drink to satisfy any thirst you might have when you’re exercising, but if your exercise isn’t extreme and it’s less than 6 hours in duration, you probably need never “replenish” your electrolytes.

[And just as a reminder of what’s in most sport drinks, below is my homemade Powerade video from a few years ago]

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Mislabelling Physical Activity a “Vaccine Against Obesity” Carries Risk

Posted May 19, 2015 by Yoni Freedhoff

“By having regular physical activity including sports and non-sport activity, movement, and not to be sedentary, it’s the best vaccine against obesity”

– Jean-Michel Borys, Director EPODE European Network, at Coca-Cola funded “Together We Move” summit.

And yet, study after study after study demonstrate that even heroic amounts of exercise seem to at best lead people to gain weight slightly more slowly, and certainly not to lose.

In kids a 10 fold difference in objectively measured daily activity did not protect again obesity, nor did the vast majority of all RCTs involving school PE in three separate meta-analyses (1, 2, 3).

In adults there was no amount of exercise that prevented weight gain in nurses in the Nurses Health Study over a 13 year period, nor was there an amount of exercise able to prevent gain in this 20 year CARDIA study, nor in this 33 year long Norwegian study.

I asked Dr. Borys two weeks ago on Twitter if he could provide me with some evidence that would support his very strong, and very Coca-Cola friendly, statement.

I have yet to hear back.

Exercise is the world’s best drug, it’s just not a weight loss drug, and saying that it is does a disservice to both exercise and weight loss.

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Post-Weight Loss Fat Gain in US Rangers

Posted May 15, 2015 by Arya M. Sharma, MD

And finally, to conclude this week’s discussion of evidence to support the notion that weight cycling predicts weight (fat) gain especially in normal weight individuals, I turn back to the paper by Dulloo and colleagues published in Obesity Reviews, which quotes these interesting findings in US Rangers: “…U.S. Army Ranger School where about 12% of weight loss was observed followi… Read More »

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Are Weight-Cycling Elite Athletes Predisposed To Weight Gain?

Posted May 14, 2015 by Arya M. Sharma, MD

My recent reading of the paper by Dulloo and colleagues on post-dieting weight gain in non-obese individuals, reminded me of my clinical observation that a surprisingly large proportion of patients I see in our bariatric clinic report a history of competitive sports. When I have previously discussed this observation with colleagues, the answer I often get is that this weight gain is simply due to … Read More »

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Rebranding Exercise: My Keynote Address for PHE Canada (Video)

Posted May 14, 2015 by Yoni Freedhoff

A few weeks ago I had the great pleasure of delivering the keynote address for Physical Health and Education Canada’s annual national conference.

The title of my talk was “Rebranding Exercise” and it makes the case for detaching exercise from weight loss and reattaching it to health.

As to why exercise needs to be rebranded? By preventing cancers, improving blood pressure, cholesterol and sugar, bolstering sleep, attention, energy and mood, and doing so much more, exercise has indisputably proven itself to be the world’s best drug – better than any pharmaceutical product any physician could ever prescribe. Sadly though, exercise is not a weight loss drug, and so long as we continue to push exercise primarily (and sadly sometimes exclusively) in the name of preventing or treating adult or childhood obesity, we’ll also continue to short-change the public about the genuinely incredible health benefits of exercise, and simultaneously misinform them about the realities of long term weight management.

Video’s below where you’ll also find links to every journal article I mention in the talk listed in order of appearance. The first 28 minutes has me covering the evidence with as much animation as standing behind a podium allows, but if you just want to see me get fired up and explain why rebranding exercise is important, skip ahead to the 28 minute mark where I extricate myself from the clutches of the podium and watch from there.

Huge thanks to PHE Canada and Doug Gleddie for the invite and to Brent Gibson from PHE Canada for recording and posting the talk.


  1. Physical activity at the government-recommended level and obesity-related health outcomes: a longitudinal study (Early Bird 37)
  2. Effect of school-based physical activity interventions on body mass index in children: a meta-analysis
  3. Physical Activity Interventions in Schools for Improving Lifestyle in European Countries
  4. Physical activity and cardiovascular risk factors in children: meta-analysis of randomized clinical trials
  5. The impact of school-time activity on total physical activity: the activitystat hypothesis (EarlyBird 46)
  6. Do extra compulsory physical education lessons mean more physically active children – findings from the childhood health, activity, and motor performance school study Denmark (The CHAMPS-study DK)
  7. Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children (EarlyBird 45)
  8. Current physical activity guidelines for health are insufficient to mitigate long-term weight gain: more data in the fitness versus fatness debate (The HUNT study, Norway)
  9. Physical activity energy expenditure has not declined since the 1980s and matches energy expenditures of wild mammals
  10. Energy Expenditure and Adiposity in Nigerian and African American Women
  11. Energy expenditure does not predict weight change in either Nigerian or African American women
  12. Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies
  13. Reduction in Obesity and Related Comorbid Conditions after Diet-Induced Weight Loss or Exercise-Induced Weight Loss in Men: A Randomized, Controlled Trial
  14. Effect of change in physical activity on body fatness over a 10-y period in the Doetinchem Cohort Study
  15. Maintaining a High Physical Activity Level Over 20 Years and Weight Gain
  16. A Meta-Analysis of Pedometer-Based Walking Interventions and Weight Loss
  17. Exercise effect on weight and body fat in men and women
  18. Effect of Exercise on 24-Month Weight Loss Maintenance in Overweight Women
  19. Impact of physical activity interventions on anthropometric outcomes: systematic review and meta-analysis
  20. Weight training, aerobic physical activities, and long-term waist circumference change in men
  21. Population estimates of Australian children’s exposure to food and beverage sponsorship of sports clubs
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Double Standards for Conflicts of Interest at the BMJ

Posted May 11, 2015 by Yoni Freedhoff

On April 8th, an editorial was published in the British Journal of Sports Medicine (published by the BMJ). The editorial had to do with the fact that exercise doesn’t seem to help much with weight loss and consequently, we should probably stop tying the two together – and it’s an opinion I share.

But today I’m not blogging about the editorial or about exercise, but rather what happened next.

Shortly after the article was published, it was removed following, “an expression of concern“.

A few weeks later and the article’s back up, and according to the journal, the concern had to do with two undeclared conflicts of interest. One author did not disclose that he is a paid advisor to Atkins, and another did not disclose that he wrote a diet book.

Curiously, on March 13th, just 3 weeks prior to the publication of this piece, another editorial, this one positing that in fact it is a lack of exercise that is driving obesity, was published by the very same British Journal of Sports Medicine.

That piece, authored by Steven Blair, Gregory Hand, and James Hill, have no author declarations of conflict whatsoever (though it does point out that the organization the editorial is announcing was funded by Coca-Cola). Yet Blair and Hill together have authored 21 books on the importance of exercise, and a quick Google search for both certainly reveal very close relationships with Coca-Cola (including this recent $2.5 million grant from Coca-Cola to Blair and Hand on the very subject of their editorial), along with a bevy of board appointments to organizations whose interests would be benefited by interest in “energy balance“.

Leaving me to wonder three things:

1. Who submitted the “expression of concern” to the BMJ?
2. Should the BMJ be doing a better job exploring authors’ conflicts before publication?


3. Are these sorts of conflicts important to disclose?

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Living The Good Life (With GoodLife Fitness)

Posted March 5, 2015 by Loukia

Spring is finally—finally—in the air.

Oh, just writing those words feels amazing! It has been a long, harsh winter, and despite a ten day beautiful vacation to Miami and Orlando, winter still dragged on, which meant I spent more time than usual sitting on the couch wishing the snow would go away so I could get outside with my children to do the things we love to do. (I’m sorry, but fun winter activities like skiing and skating are not that enjoyable to me because -30C is the worst!)

Anyway, now with warmer days in our forceast, it’s time to get back into shape. (Unless, of course, you’ve been smart and have kept up your workout routine even when all you’ve wanted to do is stay home, eat chips, and marathon-watch the new season of House of Cards.)

I have been with GoodLife Fitness for years, probably from the first year they opened in Ottawa. I loved that I could go the gym whenever I wanted to work out, I loved that there was always a location close to where I was, whether home or at work, and I especially loved the classes—like Body Pump.
I stopped going and tried another gym for a while, but I missed all that GoodLife offered me. Just as I started thinking about re-joining, I ws contacted by GoodLife Fitness to see if I wanted to work with them as a Brand Ambassador. Instantly, I said yes—there was no reason to say no to this parternship, especially because I knew it would help me achieve my fitness goals.

As a mom of two young (and very active) boys, I like to set a good example. Long walks after dinner, playing tennis, going on bike rides, and days spent swimming for hours on end in the summertime or when we’re on vacation, are just some ways we stay active while having fun. For me, though, I need more. I like the challenage of a good class, like spinning or Body Pump at GoodLife, and I love putting on my headphones and getting lost in my music as I work out on the elliptial machine. Every bit counts—that’s what I tell myself when I’m working out—and when I’m working out, I feel amazing. It’s so true, what they say, it’s like the magic cure-all. When you’re working out and burning calories, your body changes, you feel better, and you look great, too.

I love being part of the GoodLife Fitiness Blogger Ambassador Program because I have no excuses for not going ot the gym now—and the more I go, the more I love it and the more it becomes part of my daily routine. And with summer around the corner, I can’t think of a more perfect time to get in shape. After all, vacations for me are spent mostly in a bikini and I feel most confident when I’ve taken the steps to achieve a healthy body that can do it all.

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