Vol 291, 30 March 2001
What If Americans Ate Less Saturated
Text: Gary Taubes
Eat less saturated fat, live longer. For 30 years,
this has stood as one cornerstone of nutritional advice
given to Americans (see main text). But how much longer?
Between 1987 and 1992, three independent research groups
used computer models to work out the answer. All three
analyses agreed, but their conclusions have been buried
in the literature, rarely if ever cited.
All three models estimated how much longer people might
expect to live, on average, if only 10% of their calories
came from saturated fat as recommended. In the process
their total fat intake would drop to the recommended
30% of calories. All three models assumed that LDL cholesterol--the
"bad cholesterol"--levels would drop accordingly
and that this diet would have no adverse effects, although
that was optimistic at the time and has become considerably
more so since then. All three combined national vital
statistics data with cholesterol risk factor data from
the Framingham Heart Study.
The first study came out of Harvard Medical School
and was published in the Annals of Internal Medicine
in April 1987. Led by William Taylor, it concluded that
individuals with a high risk of heart disease--smokers,
for instance, with high blood pressure--could expect
to gain, on average, one extra year by shunning saturated
fat. Healthy nonsmokers, however, might add 3 days to
3 months. "Although there are undoubtedly persons
who would choose to participate in a lifelong regimen
of dietary change to achieve results of this magnitude,
we suspect that some might not," wrote Taylor and
The following year, the U.S. Surgeon General's Office
funded a study at the University of California, San
Francisco, with the expectation that its results would
counterbalance those of the Harvard analysis. Led by
epidemiologist Warren Browner, this study concluded
that cutting fat consumption in America would delay
42,000 deaths each year, but the net increase in life
expectancy would average out to only 3 to 4 months.
The key word was "delay," for death, like
diet, is a trade-off: Everyone has to die of something.
"Deaths are not prevented, they are merely delayed,"
Browner later wrote. "The 'saved' people mainly
die of the same things everyone else dies of; they do
so a little later in life." To be precise, a woman
who might otherwise die at 65 could expect to live two
extra weeks after a lifetime of avoiding saturated fat.
If she lived to be 90, she could expect 10 additional
weeks. The third study, from researchers at McGill University
in Montreal, came to virtually identical conclusions.
Browner reported his results to the Surgeon General's
Office, then submitted a paper to The Journal of the
American Medical Association (JAMA). Meanwhile, the
Surgeon General's Office--his source of funding--contacted
JAMA and tried to prevent publication, claiming that
the analysis was deeply flawed. JAMA reviewers disagreed
and published his article, entitled "What If Americans
Ate Less Fat?" in June 1991. As for Browner, he
was left protecting his work from his own funding agents.
"Shooting the messenger," he wrote to the
Surgeon General's Office, "or creating a smoke
screen--does not change those estimates."