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Jennie Smith
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a matter of genetics or diet?
Hold the fries, bring on the broccoli
BY DON PONTURO
UCLA Today
Why are Americans getting fatter? Are our genes predisposing us
to an ever-expanding waistline? Even if we know we are predisposed
to obesity or diabetes, will that knowledge motivate us to change
our lifestyles and stop supersizing our next order of fries?
Experts on nutrition pondered those questions and discussed the
many factors that are making us tip the scale at a public symposium,
“Nurturing Our Nature: Genomics, Diet and Nutrition,”
presented by the UCLA Center for Society, the Individual and Genetics
Feb. 8 at De Neve Auditorium.
“How much do our genes ordain our future health, and how
much is influenced by what we eat?” asked Edward McCabe, center
director.
Our problems with obesity and diabetes have more to do with our
couch-potato lifestyle and unhealthy diets than with our genome,
said David Heber, director of UCLA’s Center for Human Nutrition
and author of “What Color is Your Diet?” Compared to
primitive man’s, our genome is not that radically different.
But lifestyle differences are apparent in the diets of two contemporary
societies. For example, today’s hunter-gatherers who live
in the Australian Outback eat more than 800 kinds of plants, including
tubers, roots and seeds, Heber noted. In contrast, many Americans
eat only three kinds: iceberg lettuce, French fries and ketchup.
Not only are our meals richer in fat and sugar, but the portions
we eat have grown gargantuan, Heber said. In the old days, a cheeseburger
contained 280 calories. Today’s supersized giant double cheeseburger
weighs in at 1,120 calories and is filled with fat.
So if the solution is to eat more fruits and vegetables, then
why haven’t Americans made the switch?
In part, the answer is economic, experts said. Fresh produce is
expensive while less costly sugar and fat are used to make abundant
cheap food that reaps high profits with high calories. “Food
is the cheapest form of pleasure for many people,” Heber said.
While economists maintain income is the biggest factor in deciding
what you eat, social scientists and others say education and culture
play important roles. Even government policy, advertising and food
labeling have contributed to our growing bulk, said Marion Nestle,
chair of nutrition and food studies at NYU and author of “Food
Politics.”
For example, the 1994 Dietary and Supplement Act deregulated use
of dietary supplements, paving the way for gummy-bear vitamins containing
nearly 50% sugar, Nestle said. The same 1990 federal act that brought
us the nutritional facts label also allows companies that sell cereal
containing 50% corn sweeteners to display claims that their products
lower cholesterol.
The result of poor diets is becoming evident in cancer statistics.
Unbalanced diets containing too many calories or too little fiber
and micronutrients cause 35% of cancers, said speaker Bruce Ames,
director of the National Institute of Environmental Health Sciences
Center at UC Berkeley. Obesity may soon cause as much preventable
disease and death as cigarette smoking, Heber pointed out.
For now, experts are advising people to eat more fruits and vegetables,
increase activity, decrease intake of energy-dense foods and obtain
micronutrients through diet and supplements.
Or else, said Heber soberly of the younger set, “This could
be the first generation that could die before their parents from
heart disease.”
To view the presentations, go to www.arc2.ucla.edu/csig.
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