Gina Kolata. New York Times science reporter (and author of Rethinking Thin
: The New Science of Weight Loss and the Myths and Realities of Dieting) has weighed in on "carbophobia" with a review of Gary Taubes's Good Calories, Bad Calories
: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease.
Taubes's book (which, as I posted earlier, John Tierney also recently wrote about in the Times)
reports the poor science behind low-fat dietary religion and proposes
instead that carbohydrates are evil -- err, contribute to "obesity" and
disease.
Kolata acknowledges that
much of what Taubes
relates will be eye-opening to those who have not closely followed the
science, or lack of science, in this area....For example, he tells the
amazing story of how the idea of a connection between dietary fat,
cholesterol and heart disease got going and took on a life of its own,
despite the minimal connection between dietary cholesterol and blood
cholesterol for most people. He does not mince words. 'From the
inception of the diet-heart hypothesis in the early 1950s, those who
argued that dietary fat caused heart disease accumulated the evidential
equivalent of a mythology to support their belief. These myths are
still passed on faithfully to the present day.' The story is similar
for salt and high blood pressure, and for dietary fiber and cancer.
In fact, Taubes convincingly shows that much of what is believed
about nutrition and health is based on the flimsiest science. To cite
one minor example, there's the notion that a tiny extra bit of food, 50
or 100 calories a day -- a few bites of a hamburger, say -- can
gradually make you fat, and that eating a tiny bit less each day, or
doing something as simple as walking a mile, can make the weight slowly
disappear. This idea is based on a hypothesis put forth in a single
scientific paper, published in 2003. And even then it was qualified,
Taubes reports, by the statement that it was 'theoretical and involved
several assumptions' and that is 'remains to be empircally tested.'
Nonetheless, it has now become the basis for an official federal
recommendation for obesity prevention.
Yet, Kolata
points out, in his zeal to convince readers that carbohydrates make
people fat by driving up insulin levels, which encourages the storage
of fat,
...Taubes ignores what diabetes researchers
say is a body of published papers documenting a complex system of
metabolic controls that, in the end, assure that a calorie is a calorie
is a calorie. He also ignores definitive studies done in the 1950s and
'60s by Jules Hirsch of Rockefeller University and Rudolph Leibel of
Columbia, which tested whether calories from different sources have
different effects. The investigators hospitalized their subjects and
gave them controlled diets in which the carbohydrate content varied
from zero to 85 percent, and the fat content varied inversely from 85
percent to zero. Protein was held steady at 15 percent. They asked how
many calories of what kind were needed to maintain the subjects'
weight. As it turned out, the composition of the diet made no
difference.
Kolata doesn't buy Taubes's premise.
If
low-carbohydrate diets are so wonderful, why is anyone fat? Most people
who struggle with their weight have tried these diets and nearly all
have regained everything they lost, as they do with other diets.
Taubes
claims that carbohydrates are "addictive," she reports. And,
apparently, that permanent weight loss is possible if the addiction is
"'overcome with sufficient time, effort and motivation.'" Kolata isn't
convinced.
And neither am I.
Granted, I haven't read Taubes's book, but I've had plenty of
exposure to the belief (I don't really want to dignify it by calling it
a theory or hypothesis) that carbohydrates are addictive. I've seen
many fat women who were "diagnosed" as "food addicts" in a misguided
attempt to apply the 12-step program of Alcoholics Anonymous to weight,
and told they need to "abstain" from "addictive" foods like wheat and
sugar.
They've often lost weight, yes -- and then eventually started
bingeing in response to the semi-starvation, with their weight soon
returning to pre-diet setpoint levels or higher. These women had plenty
of motivation, if only due to the fat-shaming environment they grew up
and lived in. It didn't make any difference.
Taubes's book may do a service in alerting many to the poor science
behind low-fat diet orthodoxy, and how scientific consensus can cascade
into erroneous and even harmful beliefs and practices. But if he's
proposing a low-carb diet as a health (and weight) panacea, he may be
contributing to another false informational cascade.
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