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Yesterday saw the @NYTimes’ @gretchenreynold cover a recently published study about exercise and weight loss. The headline? To Lose Weight With Exercise, Aim for 300 Minutes a Week https://www.nytimes.com/2020/12/09/well/move/to-lose-weight-with-exercise-aim-for-300-minutes-a-week.html?smid=tw-nytimeswell&smtyp=cur
The story suggested more exercise may overcome our species’ habit of eating because we exercised (due to increased hunger (or maybe feelings of virtue/reward)) and concludes with this note telling us to exercise this holiday, lots and lots, to manage weight.
But what did the study actually find? Certainly, if judging from coverage in the New York Times as well as from some online exercise enthusiasts and researchers on Twitter yesterday it should be pretty impressive.
So I pulled the small short study where 19 ppl were randomly assigned to exercise for 6d/wk (averaging 320 mins/wk), 20 people for 2d/wk (averaging 189 min/wk), and 14 people who were asked to remain sedentary. All were instructed not to change their diets https://journals.lww.com/acsm-msse/Fulltext/2020/11000/Exercise_for_Weight_Loss__Further_Evaluating.22.aspx
Outcomes wise? Those exercising 320 minutes weekly lost 4lbs of body fat (will come back to this) over 12 weeks. Put another way, it took 16 hours of exercise to lose just one pound of body fat
Body fat? Well that’s definitely good to lose, but this was billed as a weight loss trial and framed in the NYTs as the thing you need to do lots and lots of to help curb holiday weight gain. Will it do that?
Um, no
From the paper, “Note: control group (N = 12) increased % weight change (+0.78 ± 1.19) and kg body weight (+0.40 ± 0.99) which was not different from exercise groups”. Meaning while body fat differed between 6d exercisers and controls, their actual weights after 12 weeks didn't
Strange that, given study title, “Exercise for Weight Loss: Further Evaluating Energy Compensation with Exercise”, the NYT’s tweet, “Exercise for Weight Loss: Aim for 300 Minutes a Week” and subhead, “Overweight men and women who exercised six days a week lost weight"
Stranger might be authors’ conclusion re: need for more effective weight-loss strategies, “Current findings provide some clarity on relevant variables & set stage for future research that may further elucidate role exercise may have or increase its utility in obesity treatment”
Reading this was depressing as it continued the longstanding bizarre fixation of researchers, journalists, and public on centering exercise’s primary role to weight despite fact that vast majority of studies demonstrate at best very disappointing weight related exercise outcomes
This belief undermines both exercise & weight management in that those who start exercising with weight loss goal may well quit exercising consequent to outcomes that are far more disappointing than they would understandably infer from studies/media/general discourse around same
And stopping exercise would be a terrible idea given its direct & indirect benefits to health, quality of life & functional independence. It also might steer people away from dietary interventions for weight loss (if weight's their goal), which might well be far more efficacious
Though slightly dated now, if you’re bored and want to hear about other exercise and weight loss studies as well as some thoughts on why I think it would be wise to rebrand exercise's benefits, here’s a talk w/linked citations I gave in the before on same http://www.weightymatters.ca/2015/05/rebranding-exercise-my-keynote-address.html
Finally, as an aside, you know what I’d love to see? A repeat of this study but w/additional intervention group of ppl instructed to remain sedentary but who receive weight related nutrition education coupled with assignment to spend 1hr/d 6 days a week on cooking & meal prep
