#30: Skeptic - V10n4 - Low carb diets are crap
OK, OK, so I'm putting a magazine in my book list but the total content
of this magazine is considerably more than many books - and is
definitely more thought-provoking. Skeptic
is a magazine that takes a critical look at topics that go
unsufficiently questioned in society. I have read issues of it before
but a couple of things stood out to me in this issue. There is a great
debunking of the urban legend that Einstein was learning disabled, a
useful guide to avoiding creationism/evolution conflicts in the
classroom, and lots of other interesting information and analysis. But
to the main event...
The cover story of this issue is titled "The Skinny on Fat" and is a skeptical look at low-carbohydrate diets. I guess I was already very skeptical of things like the Atkins diet because I have never seen any convincing evidence that anything but the "first law of thermodynamics" diet, as Bob Park puts it, will work. That diet is simple: put less energy into your body than you make it expend and you'll lose weight.
Patrick Johnson's article describes the physiological processes of food consumption and compares the claims of low-carb proponents with the scientific literature. In summary, there is no evidence that low-carb diets work. However, they could lead to very serious health problems. (As a doctor friend put it to me, "the only thing Atkins is good for is turning you into a diabetic". That may be slightly overboard but carbohydrate restriction does cause your body to have reactions very similar to those of diabetes.)
Once curious aspect of this is that your heart and liver prefer to get their energy from fat metabolism whereas your brain and red blood cells work on glycolosis (which is primarily driven by carb intake). So perhaps low-carb diets are the ultimate in self-sustaining hype - don't eat carbs, prevent energy from getting to your brain, stop bothering to analyze whether or not the diet is sensible or working...
This is an oversimplification. Your brain and red blood cells can get energy another way. Glycolosis can be driven by an indirect mechanism from fat metabolism. However, this only occurs in conjunction with ketosis, a condition also seen in poorly treated diabetes (hence my doctor friend's comment). Another side effect is a change in pH of the blood which can become ketoacidosis, a potentially life-threatening condition. Once again, the body is very resilient and there are processes that kick in and use ketones (the chemicals generated in excess during ketosis) as fuel. But do you really want to be operating your body on throwback mechanisms that appear to have arisen evolutionarily to deal with conditions where starvation is likely?
Just to add a little more gloom and doom, low-carb diets have been shown to increase low-density lipoprotein - bad cholestrol. They also increase the risks of having muscle contraction difficulties and cardiac arrhythmia. It is also plausible that extended low-carb diets could lead to osteoporosis because calcium, apparently used up in neutralizing the acidic nature of blood due to ketosis, has to be replaced from somewhere and the only likely source while on these diets is the bone. (All of these claims are documented in the article with citations to the scientific literature, unlike the claims in the low-carb diet books sold to the public.)
Do I even need to mention that there is no real evidence that low-carb diets actually make you lose weight? (Of course it will work for some people, but there are plenty of anecdotes not mentioned by the low-carb proponents about people gaining weight. Overall, there is no evidence that low-carb diets are effective for losing weight, regardless of how much they screw up your body in the process.)
When it comes down to it, the only diet that is guaranteed to work is one in which you cut down your caloric intake and increase the rate at which you burn calories, i.e. increased exercise.
(Now let's watch the low-carb proponents go apeshit and pretend they have scientific evidence for the efficacy of low-carb diets, or at least try to pretend they have evidence by telling us anecdotes.)
The cover story of this issue is titled "The Skinny on Fat" and is a skeptical look at low-carbohydrate diets. I guess I was already very skeptical of things like the Atkins diet because I have never seen any convincing evidence that anything but the "first law of thermodynamics" diet, as Bob Park puts it, will work. That diet is simple: put less energy into your body than you make it expend and you'll lose weight.
Patrick Johnson's article describes the physiological processes of food consumption and compares the claims of low-carb proponents with the scientific literature. In summary, there is no evidence that low-carb diets work. However, they could lead to very serious health problems. (As a doctor friend put it to me, "the only thing Atkins is good for is turning you into a diabetic". That may be slightly overboard but carbohydrate restriction does cause your body to have reactions very similar to those of diabetes.)
Once curious aspect of this is that your heart and liver prefer to get their energy from fat metabolism whereas your brain and red blood cells work on glycolosis (which is primarily driven by carb intake). So perhaps low-carb diets are the ultimate in self-sustaining hype - don't eat carbs, prevent energy from getting to your brain, stop bothering to analyze whether or not the diet is sensible or working...
This is an oversimplification. Your brain and red blood cells can get energy another way. Glycolosis can be driven by an indirect mechanism from fat metabolism. However, this only occurs in conjunction with ketosis, a condition also seen in poorly treated diabetes (hence my doctor friend's comment). Another side effect is a change in pH of the blood which can become ketoacidosis, a potentially life-threatening condition. Once again, the body is very resilient and there are processes that kick in and use ketones (the chemicals generated in excess during ketosis) as fuel. But do you really want to be operating your body on throwback mechanisms that appear to have arisen evolutionarily to deal with conditions where starvation is likely?
Just to add a little more gloom and doom, low-carb diets have been shown to increase low-density lipoprotein - bad cholestrol. They also increase the risks of having muscle contraction difficulties and cardiac arrhythmia. It is also plausible that extended low-carb diets could lead to osteoporosis because calcium, apparently used up in neutralizing the acidic nature of blood due to ketosis, has to be replaced from somewhere and the only likely source while on these diets is the bone. (All of these claims are documented in the article with citations to the scientific literature, unlike the claims in the low-carb diet books sold to the public.)
Do I even need to mention that there is no real evidence that low-carb diets actually make you lose weight? (Of course it will work for some people, but there are plenty of anecdotes not mentioned by the low-carb proponents about people gaining weight. Overall, there is no evidence that low-carb diets are effective for losing weight, regardless of how much they screw up your body in the process.)
When it comes down to it, the only diet that is guaranteed to work is one in which you cut down your caloric intake and increase the rate at which you burn calories, i.e. increased exercise.
(Now let's watch the low-carb proponents go apeshit and pretend they have scientific evidence for the efficacy of low-carb diets, or at least try to pretend they have evidence by telling us anecdotes.)
9:30:15 PM Your views []
