I once received a lot of blowback for an Upshot article in which I showed (with evidence) that exercise is not the key to weight loss. Diet is. Many, many readers cannot wrap their head around the notion that adding physical activity, and therefore burning more calories, doesn’t necessarily translate into results on the scale.
Well, here we go again because some of those folks also believe that fitness devices — Fitbit, Vivosmart, Apple Watch — must be helpful in losing weight. Unfortunately, evidence doesn’t support this belief either.
Yep.
Source: Wearable Fitness Devices Don’t Seem to Make You More Fit – The New York Times
It is wrong to say “exercise is not the key to weight loss. Diet is.” (NY Times). And wrong to endorse this erroneous idea with a single “Yep” (Kirk). And very wrong to choose weight loss as the sole measure of fitness, as the headline and article indicate.
The number of well-done studies of different dieting plans exceeds those for wearable fitness devices by hundreds, perhaps thousands of times. And the results are very consistent. Dieting plans, for almost all participants, do not result in long-term weight loss. Similarly, exercise programs alone don’t succeed in the long-term for most participants. Exercise, combined with diet and therapy does vastly better than any of the elements alone, and it still doesn’t produce sterling results for most people in large population trials. We don’t yet have a magic bullet, or even enough understanding of the key elements, to come up with a program that works a high percentage of the time on a lot of people. But, to date, the best results by far are from a combination program of exercise, diet, and therapy.
The NY Times article is sloppy journalism. It presents two studies on wearable fitness devices, with obvious flaws, and points out one or two of those flaws. Then it presents a somewhat larger study, which in the journalist’s description, has new and original flaws. He ignores these flaws, and I’ll ignore them too, for the moment. The reporter conflates weight loss and fitness in all of these studies. If we take the reported results at face value, participants in the two groups in the study did everything of significance to weight loss pretty much the same. The only difference was that those wearing a Fitbit lost an average of 7.7 pounds in 18 months, while the others lost 13 pounds. So, everything else being equal, wearing a Fitbit cuts your weight loss roughly in half.
This result tells us that the study has either discovered something miraculous about wearing a fitness device, whose mechanism for fighting weight loss is unexplained, or that there were important differences between the two groups in the study, which were not accounted for, or not reported, at least in the NY Times article.
I don’t think the “ten thousand steps” plan is relevant to weight loss. It’s too little exercise, at two low an energy level. But it has the potential of improving health for a large number of people. I know dozens of people who use a step counter, and have increased their daily activity by two thirds or more. That means that they have increased from an almost totally sedentary lifestyle to one that includes meaningful amount movement throughout the day. I don’t know if the 10,000 step regimen has been specifically tested as a factor in cardiac, circulatory, or general health, but the risks of being totally sedentary are well established.
It is wrong to say “exercise is not the key to weight loss. Diet is.” (NY Times). And wrong to endorse this erroneous idea with a single “Yep” (Kirk). And very wrong to choose weight loss as the sole measure of fitness, as the headline and article indicate.
The number of well-done studies of different dieting plans exceeds those for wearable fitness devices by hundreds, perhaps thousands of times. And the results are very consistent. Dieting plans, for almost all participants, do not result in long-term weight loss. Similarly, exercise programs alone don’t succeed in the long-term for most participants. Exercise, combined with diet and therapy does vastly better than any of the elements alone, and it still doesn’t produce sterling results for most people in large population trials. We don’t yet have a magic bullet, or even enough understanding of the key elements, to come up with a program that works a high percentage of the time on a lot of people. But, to date, the best results by far are from a combination program of exercise, diet, and therapy.
The NY Times article is sloppy journalism. It presents two studies on wearable fitness devices, with obvious flaws, and points out one or two of those flaws. Then it presents a somewhat larger study, which in the journalist’s description, has new and original flaws. He ignores these flaws, and I’ll ignore them too, for the moment. The reporter conflates weight loss and fitness in all of these studies. If we take the reported results at face value, participants in the two groups in the study did everything of significance to weight loss pretty much the same. The only difference was that those wearing a Fitbit lost an average of 7.7 pounds in 18 months, while the others lost 13 pounds. So, everything else being equal, wearing a Fitbit cuts your weight loss roughly in half.
This result tells us that the study has either discovered something miraculous about wearing a fitness device, whose mechanism for fighting weight loss is unexplained, or that there were important differences between the two groups in the study, which were not accounted for, or not reported, at least in the NY Times article.
I don’t think the “ten thousand steps” plan is relevant to weight loss. It’s too little exercise, at two low an energy level. But it has the potential of improving health for a large number of people. I know dozens of people who use a step counter, and have increased their daily activity by two thirds or more. That means that they have increased from an almost totally sedentary lifestyle to one that includes meaningful amount movement throughout the day. I don’t know if the 10,000 step regimen has been specifically tested as a factor in cardiac, circulatory, or general health, but the risks of being totally sedentary are well established.