Nobody disputes the obvious fact that it is possible to make anyone lose weight—starvation is one classic method that has been around for a long time. But that isn’t the problem. We know how to make a person thinner, but we don’t know how to make people thinner, because people like to eat fatty foods, they like to be sedentary, they dislike dieting and often don’t have the willpower for it. Having an effective diet is only part of a solution if people are resistant to it.
Saying calorie restriction is a way to make people thinner is like saying quitting cigarettes is a way to lower cancer rates: not true enough.
Yes: diet and exercise. That’s exactly how you make people thinner. The problem—there are competing truths here—is that diet and exercise isn’t the easy solution it seems to be. How do you implement calorie restriction and exercise? This is what Paul is talking about when he says we don’t know. (But I think his choice of words suggests that the “diet and exercise” message is debunked or something.)
Re: “There aren’t any health differences to speak of for people between BMIs of about 20 and 35”
Uh, reality check!
There not any doubt that health is affected over this range (imagine here the BMI of a single individual varying over this range) but the problem—to mediate again—is that BMI is not a reliable measure of unhealthy fat, so you can’t accurately compare the health of two different people by their BMIs, or really have a good gauge of your own health from your current BMI. Paul Campos is exploiting this confusion. It would be incorrect (and intellectually dishonest) to connect this message about BMI with the message that it’s just as healthy to be 30 pounds overweight.
Some discussion of the connection between health risks and BMI here and the limitations of BMI as a measure here.
I haven’t read the book, so I don’t know if Paul Campos actually asserts that being fat is healthy, and unrelated to diet and exercise, or if he is deliberately misleading in order to whip up interest in his book.
Yet there’s at least one true message: for people who have a healthy weight but a high BMI (for their height, thanks Psychohistorian), they can consider themselves healthy because they’re not overweight.
This is a little vague. “Healthy weight” is contingent on height, so the term is, at least, imprecise in this context. I’m guessing your point is that BMI is contingent on build as well as height, which is absolutely true and which the article you linked kind of misses out on.
BMI assumes that people get thinner (or relatively slighter-framed) when they get taller which I believe is generally but not universally true, and it assumes people don’t have a lot of muscle. There’s enough variance in the population that there will be people with builds that do not conform BMI’s assumptions (Schwarzenegger, as a famous example). BMI gets used so frequently not because it is accurate but because it is super, super easy to measure. If the theory works, it’s useful for populations, if not for individuals, because populations shouldn’t see lots more muscular people or major changes in average frame.
It’s possible that changes in average BMI are partly unrelated to more people being dangerously overweight—for example, different ethnicities may have some variance in their builds, and the original design of the BMI scale almost doubtlessly failed to account for this, so changes in ethnic composition could affect BMI without actually being a health problem. But BMI is a nice scapegoat because of its imprecision when dealing with individuals; it really isn’t meant to measure them. If its being used to study populations, it’s useful if potentially misleading. If it’s being used by individual doctors with individual patients, that could be a serious problem.
I’ll admit I’m a bit biased on this whole issue, as I’ve found BMI to be quite inaccurate personally.
Re: “I mean, there’s no better established empirical proposition in medical science that we don’t know how to make people thinner.”
Uh, calorie restriction is safe, reliable and effective.
Re: “There aren’t any health differences to speak of for people between BMIs of about 20 and 35”
Uh, reality check!
Nobody disputes the obvious fact that it is possible to make anyone lose weight—starvation is one classic method that has been around for a long time. But that isn’t the problem. We know how to make a person thinner, but we don’t know how to make people thinner, because people like to eat fatty foods, they like to be sedentary, they dislike dieting and often don’t have the willpower for it. Having an effective diet is only part of a solution if people are resistant to it.
Saying calorie restriction is a way to make people thinner is like saying quitting cigarettes is a way to lower cancer rates: not true enough.
Yes: diet and exercise. That’s exactly how you make people thinner. The problem—there are competing truths here—is that diet and exercise isn’t the easy solution it seems to be. How do you implement calorie restriction and exercise? This is what Paul is talking about when he says we don’t know. (But I think his choice of words suggests that the “diet and exercise” message is debunked or something.)
There not any doubt that health is affected over this range (imagine here the BMI of a single individual varying over this range) but the problem—to mediate again—is that BMI is not a reliable measure of unhealthy fat, so you can’t accurately compare the health of two different people by their BMIs, or really have a good gauge of your own health from your current BMI. Paul Campos is exploiting this confusion. It would be incorrect (and intellectually dishonest) to connect this message about BMI with the message that it’s just as healthy to be 30 pounds overweight.
Some discussion of the connection between health risks and BMI here and the limitations of BMI as a measure here.
I haven’t read the book, so I don’t know if Paul Campos actually asserts that being fat is healthy, and unrelated to diet and exercise, or if he is deliberately misleading in order to whip up interest in his book.
Yet there’s at least one true message: for people who have a healthy weight but a high BMI (for their height, thanks Psychohistorian), they can consider themselves healthy because they’re not overweight.
This is a little vague. “Healthy weight” is contingent on height, so the term is, at least, imprecise in this context. I’m guessing your point is that BMI is contingent on build as well as height, which is absolutely true and which the article you linked kind of misses out on.
BMI assumes that people get thinner (or relatively slighter-framed) when they get taller which I believe is generally but not universally true, and it assumes people don’t have a lot of muscle. There’s enough variance in the population that there will be people with builds that do not conform BMI’s assumptions (Schwarzenegger, as a famous example). BMI gets used so frequently not because it is accurate but because it is super, super easy to measure. If the theory works, it’s useful for populations, if not for individuals, because populations shouldn’t see lots more muscular people or major changes in average frame.
It’s possible that changes in average BMI are partly unrelated to more people being dangerously overweight—for example, different ethnicities may have some variance in their builds, and the original design of the BMI scale almost doubtlessly failed to account for this, so changes in ethnic composition could affect BMI without actually being a health problem. But BMI is a nice scapegoat because of its imprecision when dealing with individuals; it really isn’t meant to measure them. If its being used to study populations, it’s useful if potentially misleading. If it’s being used by individual doctors with individual patients, that could be a serious problem.
I’ll admit I’m a bit biased on this whole issue, as I’ve found BMI to be quite inaccurate personally.