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Efficacy vs. Effectiveness for Diet and Exercise.

25 October 2016

There was recently a big hubbub about flossing. It turns out that flossing is efficacious (i.e., it can work) but not effective (i.e., it doesn’t benefit people as it is ordinarily practiced). That is, there is evidence that when a person flosses as directed for a long period of time, that person will usually have healthier teeth than a person who doesn’t. But at the population level, flossing isn’t effective because almost no one actually does it like that. And so there’s no evidence, when you compare two groups, one of which says they floss, and another that doesn’t, that the flossing group has healthier teeth on average.

I suspect diet and exercise for weightloss is similar. We have all these studies that show the various metabolic and physical responses to various interventions. Some say diet is better. Some say exercise is. But what almost everyone agrees on is that over time people gain weight back and most people don’t achieve lifelong weightloss. Once a person is obese, they may be able to make short term impacts, but long term BMI reduction is very rare. This has led many people to conclude that there’s no hope for weightloss, and we should focus on other aspects of metabolic health.

Now, it is certainly true that people’s metabolisms slow as they age, and getting the same bang for one’s buck, diet and exercise-wise, gets more difficult as we get older. Also, as time goes by, people are at risk of injury and disease which may impact their ability to maintain a diet and exercise regimen. But those strike me as rarer than the most common issue people face. Dieting is hard, and sucks. Exercise is hard, and sucks. So we quit.

We often create diet and exercise goals, like losing a specific number of pounds, or accomplishing an exercise challenge like a race. Then, when we’ve achieved it, we stop doing the things that got us there. We reward ourselves with treats and rest, which disrupt our routine, and eventually end our investments. We treat these goals as if, once achieved, our bodies never change again, so we can stop doing the things it took to get us there.

We know that diet and exercise are efficacious. The laws of thermodynamics require them to be. If you limit the input of energy, and increase the expenditure of energy, eventually, your body will be forced to decrease mass to compensate for the flux. There will be issues, like metabolic changes that conserve energy, etc., but there is only so much conservation one’s body can do.

But diet and exercise are not, by and large, effective. Because people don’t do them well, or sufficiently, or for a long enough time. The caloric deficit one has to maintain for a weightloss of 50 pounds, like I did, is enormous and challenging. I have spent time and effort for years, and it’s been difficult and painful. I’ve had injuries, I’ve had setbacks, I’ve had to commit to an entirely different way of life from the one I used to have, and it’s had to be permanent.

Diet and exercise are at least somewhat similar to abstinence as a treatment for addiction. We know good and well that if you don’t drink, if you don’t take drugs, you don’t get drunk and you don’t get high. But telling an alcoholic, “just don’t drink,” or an addict, “just don’t use,” is not an effective treatment, no matter how efficacious it would be if they followed the advice. Most addicts will never stop using. Most addicts will die in active addiction. We don’t know how to make efficacious treatments more effective, mostly.

The same is true, I think, for diet and exercise. Changing lifestyle is hard. It’s not a matter of will, I know that from my own experience being sober now for more than 8 years. It takes a sea-change of behavior that I’m not certain how to describe. It takes seeing one’s self and one’s life in a new way. It takes effort and determination, yes, but it takes something else as well. Not something more, maybe not internal at all. Certainly, I could not stop drinking alone.

I don’t know why I’ve been able to make life changes and other people who want to just as badly can’t. I know it’s not about money or time, because I know people with less of both who’ve succeeded better than I have – though I admit money and time have made my path easier. It’s not will. It’s not intelligence.

Maybe it’s just luck. Maybe I’m just lucky that making wholesale lifestyle changes agrees with me. That I am enriched and satisfied, internally, by the kinds of things I have to do to achieve these things. I don’t know. I don’t know how to pass it on. I wish I did. Because the things I have accomplished in sobriety and in fitness have brought me joy and pride and capability. I wish I knew better how to share them.

9 Comments leave one →
  1. Aimee permalink
    25 October 2016 13:10

    We have always known anecdotally that metabolism slows with calorie restriction, but recent research has shown there’s a lot more play in the system than anyone had guessed. Apparently some unlucky people can experience their metabolism slow by 40% after prolonged calorie restriction. And it never returns to “normal.” Thr means that forevermore that person would have to live on 60% of a “normal” calorie diet for the rest of their lives just to maintain weight. Backslide even a little bit, and you’re going to regain the weight faster and faster each time. So from a purely rational analysis, I look at the problem and think – do I believe I can maintain that kind of calorie restriction forever? No, I don’t. I have zero evidence from any realm of my life that I have the discipline to maintain ANYTHING. If I can’t maintain a clean toilet or a secondhand car, why on gods green earth would I think I can live on a little over half the amount of food I’ve been eating for the rest of my
    life? And given that the consequences of yo-yo weight loss and gain are steep and dangerous to my health, and that I have an essentially zero statistical chance of ever losing enough weight so as to no appear normal anyway – well, it just starts to look like a really bad bet. On the one hand – everything stays the same. You stay fat and you get to live your normal life. Maybe you keep getting slowly heavier at a rate of a few pounds a year. On the other hand, you dedicate your entire life to changing your diet and habits, you upset your family and make extra work for yourself eating differently from them, you think of nothing else day or night – and you almost certainly stay fat anyway – just a little less fat. And if you find you can’t keep it up, you get fatter than you’ve ever been yet. To me it sounds like it boils down to this: “am I a regular human, like 99.8 % of other humans, who get typical results? Or am I a superhuman who can buck the odds and be an extreme outlier?” Yeah, I know the answer to that question.

    • Aimee permalink
      25 October 2016 13:14

      All of which doesn’t even begin to address the question of why someone like myself, who is fat but basically healthy- should even feel that losing weight OUGHT to be the most important thing in their life. I mean, seriously. Am I living a fate worse death here? Is my life so hideous, my body so grotesque, that the only right thing to do is dedicate myself to changing it, no matter how slim the odds? That’s an offensive assumption (which I know you don’t hold, BTW, it just often feels that everybody does).

      • Aimee permalink
        25 October 2016 13:32

        I think the question can be framed as “are you a) willing and b) capable of becoming a lifelong fanatic?” And in my case the answer to parts a and b both is “no.”

      • 25 October 2016 13:36

        I’m not sure “fanatic” is an appropriate characterization of the lifestyle required to maintain fitness and healthy bodyweight. Perhaps to regain it once lost.

        But NONE of this, as you know, should be taken to mean that anyone SHOULD do it. Merely rumination on what it takes if someone WANTS to.

    • 25 October 2016 13:14

      I think that mixed in with the reasonable stuff there is a lot of rationalization and bad statistics.

      • Aimee permalink
        25 October 2016 13:18

        I won’t argue the rationalization, but the stai sticks are perfectly clear. The
        Number of people who manage to lose the amount of weight that I have to lose and keep it off (without surgery anyway) are so few as to be basically statistically insignificant.

      • 25 October 2016 13:21

        I was thinking about the 0.2%, and what it means to be in that group or not? The number that will lose 100+ pounds – and keep it off – if they start trying? Yeah, maybe. But the # that can lose a health-significant and QoL-significant amount of weight (about 5% of bodyweight) with a basic effort? I believe it’s much larger than that.

      • Aimee permalink
        25 October 2016 13:31

        Yes, many many more can lose 5% of their weight and keep it off for long periods of time. I don’t know what the stats on that are – still fairly grim id bet. But that still leaves me as “the
        Person no one wants to sit next to on a plane.” We’ve talked about this before.

      • Aimee permalink
        25 October 2016 13:34

        I think the question for me is “are you a) willing and b) capable of becoming a lifelong fanatic?” And my answer to parts a and b both is “no.”

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