May 13, 2009 7:33 pm US/Pacific
How Sugar Hijacks Your Brain
(CBS 5)
This is Part 3 of Dr. Kim Mulvihill's series on sugar. Click for:
Part 1: The Bittersweet Truth About Sugar
Part 2: Sugar Molecule Linked to Liver Damage.
Part 4: Waging War on Sugar to Win the Battle of the Bulge
Part 5: Experts Weigh In On Stopping the Obesity Crisis
Part 3:
In 1995, when we first met the Niles, Shawn, at 5 foot 8 inches, weighed in at 230 pounds. His 5-foot-four inch wife Debbie was at 212. With a change in diet and exercise, in six short months, each lost 50 pounds.
But when we saw them again in 2002, they had both gained all that weight back.
Debbie explained that they kept it off for two years, but then old habits came back and they started eating more convenient prepared and processed foods. And by this point, each now had some health problems: pre-diabetes, high blood pressure, high cholesterol.
We called the Niles recently and asked if we could drop by again. Both had lost weight again: Shawn is down 70 pounds. Debbie has lost half her body weight, and is now at 120. She's kept the weight off for 5 long years.
"People don't remember me at 240 pounds," she says. "They remember me more now."
As to what makes this time different? Debbie believes she has the answer:
"I realized that what was causing the weight was my addiction to sugar," she says, adding that she remains addicted to sugar now.
There's no doubt americans love the sweet stuff. We consume more sugar and sweeteners than any other country in the world. However, at what point does a sweet tooth become a sweet fix?
Some researchers believe too many sugars can hijack the brain, stoke the appetite, and lead to chronic overeating. Pediatric endocrinologist Dr. Robert Lustig of UCSF says there are very specific effects of sugar on the reward center of the brain. He says the problem is the fructose, a molecule found in sugars and sweeteners. Dr. Lustig says if you binge on sweets, all that fructose unleashes a surge of dopamine in the brain. Dopamine is a neurotransmitter that plays a major role in addiction.
"You need more dopamine and the only way to do that is by consuming more food," Dr. Lustig explains.
Former FDA Commissioner Dr. David Kessler, who is also at UCSF, has a different take. He believes it's not just sugars, but processed foods and drinks loaded and layered with sugars, salts, and fats that are the problem. He calls the phenomenon "conditioned hyper eating."
"What we see are areas of the brain become activated, the dopamine levels rise, and they don't habituate they don't shut off until all the food is gone," he says.
Both researchers believe changes in the brain are leading to chronic overeating that's feeding an obese nation.
The Sugar Association says sugar is not addictive, that the claim is a myth, and that dopamine is released whenever you consume any food or beverage, even sugar-free sodas.
Dr. James Rippe is a cardiologist who speaks for the Corn Refiners Association. He says when it comes to America's obesity epidemic, don't blame high fructose corn syrup.
"Rather than saying 'Gee we're eating too much,'" Dr. Rippe says, "Or 'We're not active enough' -- It's very convenient to try find a smoking gun. It's very convenient to say well it must be high fructose corn syrup. Convenient, but wrong."
As for the Niles, since their weight loss, their cholesterol and blood pressure are now normal, and they're no longer pre-diabetic. When they want their daily sugar fix, they're hooked on fresh fruits. Deb Niles believes there is nothing more delicious than eating apples or strawberries. She also carefully reads food labels and won't consume any product that has more than 5 grams of sugars per serving.
What's 5 grams? That's a little over a teaspoon.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
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