Could 'Extreme' Low-Cal Diets Bring Longer, Healthier
WEDNESDAY, May 25 (HealthDay News) -- Science has shown that
diets that veer close to starvation can make everything from mice
to monkeys live longer.
But can such a strict eating regimen prolong human lives, and if
so, would those extra years be healthy, happy ones?
Recent research from Washington University scientists found that
people who slashed their calorie intake have lower core body
temperatures than those who eat more. Core body temperature is the
temperature at which all of the functions in the body can operate
at maximum efficiency, so the link looks like a positive one,
according to some researchers.
Trent Arsenault, a 35-year-old engineer in the Bay Area,
certainly hopes so.
He has been a "calorie restrictor" since 2000, consuming just
1,800 calories a day or 25 percent less than what a male of his
size -- 6-foot-1 and 150 pounds -- would normally consume, he
Since he started, he has shed 60 pounds and now has a body-mass
index of 19, just one notch above underweight (which is 18). His
body fat composition is only 10 percent.
Arsenault is also one of 28 participants in the first long-term
clinical trial to look at extreme calorie restriction in humans,
and its effects not only on longevity but also on health.
He was recruited with the help of the Calorie Restriction
Society, an international organization with several thousand
The study is known as CRONA (Caloric Restriction with Optimal
Nutrition and Aging Study). It is being done at the University of
California, San Francisco, where participants from many different
states as well as England and Japan are traveling for a weekend of
tests including cognitive exams, body measurements and a visit to
an egg-shaped chamber that measures body fat composition. They'll
also complete surveys on everything from their medical history and
eating habits to sleep patterns and stress levels.
"It's an interesting paradox because restriction in animals seems to be the fountain of youth, but all my prior work in humans has shown not such great outcomes," said Janet Tomiyama, a psychologist who is a Robert Wood Johnson Foundation Health & Society Scholar at UCSF and principal investigator of this trial.
And the animal studies haven't had clear data on how
well the animals are actually living.
"The animal data seems good with all the longevity studies but what people really don't know is how healthy the animals actually are," said Heidi A. Tissenbaum, an associate professor in the Program in Gene Function and Expression and in molecular medicine at the University of Massachusetts Medical School in Worcester. "How happy are the people? Are they feeling restricted all their life?"
Not only will the investigators be looking at cholesterol and
other markers of health, but they will also measure the length of
telomeres. These are pieces of DNA which, when shortened, seem to
be linked with health problems and a shorter lifespan.
Among other things, the study will look at how personality might
differ in calorie restrictors compared to normal eaters or
overweight/obese people, as well as cognitive ability, impulse
control and how stress is handled.
The study participants are mostly male (as are most calorie
restrictors), well-educated and middle-aged.
It will take decades to have results from the trial but
Arsenault feels he already has seen a difference.
He doesn't catch colds or the flu, has plenty of energy and
neither his sexual drive nor his fertility have been affected, he
said. In fact, he has fathered at least 15 children through a sperm
bank since he started restricting calories.
Unlike many calorie restrictors, Arsenault did not have a
mid-life health scare which propelled him into action. Instead, at
the age of 25, he realized he wanted to concentrate on his career,
postponing marriage and children.
"[I wanted to] keep myself looking decent enough so that in 10 years I could get married and still be healthy enough to spend time with kids," he explained.
The study is funded by the Appleby Foundation, the Robert Wood
Johnson Foundation Health & Society Scholars program and the
University of California, Berkeley Population Center.
Researchers Elizabeth Blackburn, Elissa Epel and Jue Lin are
also co-founders of a new company called Telome Health Inc., which
is developing applications of telomere biology to improve
For more information on this type of lifestyle, visit the
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