There are a lot of health and fitness myths out there. And there are a lot of bogus health products and practices being sold on the basis of those myths. In fact, a strong argument could be made that 90 percent of the entire fitness and diet industry is based on a foundation of myth, lies and hyperbole.

One of the most enduring and significant " at least from the perspective of market share " is the idea that we can ”œspot reduce” or tone a particular part of our bodies. Think of the number of fitness products built on this falsehood. Think of the billions and billions of dollars that have been wasted on devices that promise to twist, bend and shake away our fat. From Dr. Walter’s Medicated Rubber Garments " a device that will, according to a 1910 advertisement, ”œspeedily reduce superfluous flesh in any part of your body” " to Suzanne Somers’ iconic ThighMaster, the dream of easy fat reduction and ”œbody shaping” has been with us forever. The Neanderthals probably rubbed mammoth fur on their flabby bellies.

To be clear: it is biologically impossible to lose fat from a specific part of the body by exercising that particular part of the body. The only way to reduce belly, arm, thigh or butt fat is to lose enough fat from your entire body to reduce the fat at the desired location. Without a healthy diet, no amount of arm lifts will give you Jennifer Aniston’s arms. You can’t Zumba or Brazilian-butt-lift your way to a slim rear end. You can’t get ”œamazing arms for your wedding day” " a current fitness-marketing craze " by doing a series of magical arm workouts. You won’t get a long and lean look by doing yoga or Pilates (what the heck are long lean muscles?). And the most desired of all physical qualities, sexy abs, come from one thing: having a low percentage of body fat. For a man, you probably need to get it down to around 10-12 percent, which is pretty darn low.

The ThighMaster will do little or nothing to get you to this destination.

OK, so why rant about this ubiquitous myth? For one thing, to simply try to stop people from wasting their money on useless products. More importantly, I believe the spot reduction myth " which, if anything, seems to be gaining strength thanks to celebrity endorsements and social media fetishizing of particular looks (for example, the ”œthigh gap” craze) and body parts " makes it more difficult to promote realistic, health-improving and sustainable approaches to fitness.

Despite the myriad evidence-based health benefits associated with exercise " protection against dementia and depression, improved sleep and quality of life, reduction in the risk of numerous chronic diseases, etc., etc. " the primary reason people exercise is to improve the way they look. Aesthetics is a chief motivator for our health-related behaviours.

It is impossible to lose fat from one part of the body by exercising that part of the body.

There is ample evidence to support this reality. A 2014 study from Concordia University by James Gavin et al., for instance, found that no matter the age, the primary incentive for physical activity across the lifespan was to be ”œtoned and fit.” As people age, the relevance of maintaining health does become a more salient motivating factor, but aesthetics and things like ”œbody shaping” remain an important part of the equation. The authors speculate that this may be because people seek to ”œcounter the effects of aging.” Another fascinating study on point, published in 2002 in the journal Ageing and Society, found that even for women between the ages of 61 and 92, ”œperceived appearance dividends are the key motivation behind altering one’s body weight in later life.”

In July Statistics Canada released the results of a study by D. Garriguet and R.C. Colley that found that if exercise is measured objectively " that is, actual physical activity as compared with reported physical activity " only 10 percent of teens and 15 percent of adults satisfy existing (and darn modest) exercise guidelines. Clearly, the desire for sexy abs isn’t doing the trick. To be fair, the reasons people do and don’t exercise are complex. There are, for example, socio-economic barriers and real and perceived time constraints (the average Canadian watches about 30 hours of TV per week!). But the emphasis on looks and trying to shape particular parts of our bodies, as opposed to embracing exercise for more intrinsic reasons, doesn’t seem to be helping.

The spot reduction/toning mentality frames exercise as a task that must be endured to achieve a very specific goal. When exercise is viewed as work we are less likely to do it and more likely to quit if/when the goal is achieved (or when the impossibility of attaining the sexy-abs end point becomes apparent), and there is an increased chance we will reward ourselves with food, thus nullifying any calorie burn benefit (admittedly, 10 minutes on the ThighMaster likely burns the equivalent of less than one Hershey’s Kiss).

For example, a 2014 study out of the Cornell Food and Brand Laboratory found that people eat much less if they perceive the relevant physical activity as fun rather than as a specific exercise. People tend to reward themselves with food after a workout and, I suspect, this is particularly true when the exercise is as tedious as many of the spot reduction routines are.

Somehow we need to make physical activity a natural and expected part of our lifestyle. And we need to emphasize the numerous very tangible benefits of exercise. The fitness industry preys on our desire for sexy abs " leveraging and, at the same time, helping to create unrealistic expectations that sell products. For must of us, sexy abs are entirely unattainable. But being fit and active is not.

I admit there is probably little that can be done to reverse the exercise-for-looks trend. Our obsession and concern about physical attractiveness has a long history and, no doubt, a strong evolutionary basis. And, sadly, looks are important. Studies have consistently found, for instance, that attractive people make more money.

But let’s try to nudge things in a different direction. Let’s kill the spot reduction myth once and for all. Suzanne Somers doesn’t need any more of our money.

Timothy Caulfield holds the Canada Research Chair in Health Law and Policy at the University of Alberta, is a Trudeau Fellow and is the author of The Cure for Everything: Untangling the Twisted Messages about Health, Fitness and Happiness (Penguin 2012).