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Daniel G. Amen, M.D Headshot

Psychodiabetes: Sugar on the Brain

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Have you ever seen a feeding frenzy? A terrifying YouTube video of dozens of huge, ravenous sharks literally flying through the air as they savagely attacked prey fish at the Jersey Shore has gone viral. Or perhaps you've tuned into a nature show on the Discovery channel and watched hyenas fighting over a kill, growling and clawing each other to consume a few precious calories of protein.

Something akin happened in the human world last year when hordes of consumers stampeded to their supermarkets to snap up every Hostess snack cake they could find, after the company announced it was going out of business. There were even fights over the last few boxes of Twinkies.

Now the battleground has shifted to jumbo-sized sugary beverages, as a state judge has overturned New York's controversial ban on belly-busting drinks, the day before it was to take effect.

In a ruling that's been hailed as "a major victory" for the soft drink and fast-food industries, state Supreme Court Justice Milton Tingling called regulations prohibiting restaurants, movie theaters and other food-service enterprises from serving sugary drinks in sizes larger than 16 ounces "capricious and arbitrary."

New York City's mayor, Michael Bloomberg, vows to continue the fight against mega-drinks, while Boston's mayor has ordered a phase-out of sales and ads for sugar-laden beverages from municipal buildings and city-sponsored events.

Liquid Candy and Brain Chemistry

The American Beverage Institute, which sued New York City to block the super-sized soda ban, issued a celebratory statement captioned, "Choice Lives!" Arguing against any "one-size-fits all policy" that would limit the public's ability to swill sugary mega-drinks with reckless abandon, the statement contends in part that, "health cannot be legislated, mandated or decreed -- it must be learned and practiced by individuals."

Among the many ironies in this situation, one of the most profound is that for many people, guzzling ever-larger sugary drinks or even fighting like crazed addicts to get their last Twinkie fix is no longer "a choice." Instead, more and more Americans are becoming addicted to sugar, even as it destroys their health.

Harvard University's School of Public health reports on its website, "Strong evidence indicates that our rising thirst for 'liquid candy' has been a major contributor to the obesity and diabetes epidemics." New research has also linked a sugar-laden diet to Alzheimer's disease, which some scientists are now calling "Type 3 diabetes."

What's fueling this insatiable thirst? Our eating behavior is governed by some of the most primitive parts of our brains -- neurochemical reward systems that drive us to seek out foods that, in Paleolithic times, helped us survive. Amongst the most important of these was sugar.

Despite the tremendous change in our civilization and food culture, our genes have changed relatively little over the last 10,000 years. And our DNA drives us to seek out foods that would have helped keep our ancient ancestors alive. Sugar and fat topped that list for obvious reasons: High in calories, they were traditionally they were found in foods that were packed with essential nutrients -- such as fruits, vegetables, and animal products.

New brain science suggests that we've developed an internal reward system that makes us crave foods that once helped us survive, making it hard to kick the sugar habit, even amid mounting evidence that it's toxic -- and even lethal -- beyond its calories. In fact, a recent report published in the journal Nature linked sugar to 35 million deaths a year globally from diseases like diabetes, heart disease and cancer.

In the Nature report, Robert Lustig, M.D. and other UCSF researchers contend that sugar's alarming potential for abuse, coupled with its toxicity and pervasiveness in the Western diet, makes it the primary culprit in a worldwide health crisis. At the levels eaten by most Americans, its hazards mimic the effects of alcoholism, Dr. Lustig and colleagues note in their paper.

Is Sugar More Addictive than Cocaine?

Recent research has shown that eating something sweet can actually be more rewarding than cocaine. In a study published in the journal PLoS One, researchers took two groups of rats and let them choose between water sweetened with saccharine and intravenous cocaine. The results were stunning.

A whopping 94 percent of the animals chose the sweetened water over cocaine. As if this weren't enough to astonish the researchers, they repeated the experiment using sucrose -- regular table sugar. The results were exactly the same: The rats continued to choose sweet flavors over cocaine even after they had been injected with the drug and the amounts were escalated in patterns classically seen in addicts. No matter how much cocaine the rats received, the vast majority of them preferred sugar.

Here is what the researchers concluded:

Our findings clearly demonstrate that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals. We speculate that the addictive potential of intense sweetness results from an inborn hypersensitivity to sweet tastants. In most mammals, including rats and humans, sweet receptors evolved in ancestral environments poor in sugars and are thus not adapted to high concentrations of sweet tastants. The supranormal stimulation of these receptors by sugar-rich diets, such as those now widely available in modern societies, would generate a supranormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction.

The Hidden Smoking Gun in Alzheimer's

You might ask, "Why is this a problem? If our genes predispose us to eat sugar, why not honor that ancient mandate?"

The answer is that we have access to way too much sugar in today's world -- far more than our bodies can properly metabolize. Our ancient ancestors ate only about 22 teaspoons of sugar a year. Today's Americans consume an average of 52 teaspoons of added sugar per day, according to the USDA, which calls the sweetener "the number one food additive."

Not only is sugar overload making Americans overweight and cavity-prone, but new research also shows that our national sweet tooth is leading to "brain decay," a condition that I refer to as "psychodiabetes."

While it's long been known that diabetics are at higher risk for dementia, a shocking 2012 study found that key brain areas start shrinking when blood sugar hits the high end of the "normal" range, even when such cofounders as smoking, high blood pressure and alcohol consumption were taken into account.

In the study, adults ages 60 to 64, with normal fasting blood sugar, as defined by the World Health Organization, underwent brain scans. When the scans were repeated four years later, those with higher blood sugar showed more shrinkage (atrophy) in the brain's hippocampus and amygdala -- both of which play a key role in memory and mental skills -- compared to those with lower blood sugar.

Scarier still, another recent study reported "accelerated cognitive decline" in teens who ate a high-calorie junk food diet! What both studies reveal is that our brains can develop insulin resistance, the malady that leads to Type 2 diabetes.

Why does a sugary diet shrink your brain? A major study out of Harvard Medical School demonstrated that eating large amounts of high-glycemic carbs amps up the body's inflammatory response. The scientists measured levels of the inflammatory marker C-reactive protein (CRP) and found that people who ate the most sugar had the highest -- and most dangerous -- levels of CRP.

Many studies link inflammation -- fueled by sugar, a poor diet, obesity, and our increasingly unhealthy lifestyle -- to a host of chronic illnesses, from heart attacks and strokes to Type 2 diabetes, Alzheimer's and even cancer. In fact, some experts even theorize that this fiery process may be the root cause of all non-communicable disease.

In short, if your body -- and brain -- are on fire, your disease risk skyrockets.

Why You Need to Kick the Sugar Habit Now

Lest you think that only your memory is at stake (as though dementia isn't bad enough!) insulin resistance has been linked to a wide array of behavioral and mood disorders, including depression, panic attacks, anxiety, insomnia, and ADHD. In fact, a recent study shows children who are given sugar every day have a significantly higher risk for violence later in life.

As I report in my new book, Unleash the Power of the Female Brain, sugar on your brain affects mood, memory, cognitive performance and more. But the good news is that "diabetes of the brain" is preventable. To keep your brain sharp, I offer a simple prescription: Go cold turkey in kicking the sugar habit. In other words, start eating like a diabetic, so you never become one.

I disagree with those who say, "Everything in moderation." Would you want your child taking heroin in moderation -- or your spouse having affairs in moderation? If you want to protect your brain, you need to get off the sugar. A good way to identify foods that rapidly convert to sugar in your bloodstream is by getting to know the glycemic index.

The glycemic index rates carbs according to their effects on blood sugar, using a scale of one to 100+. Glucose is 100, while healthy foods are lower on the scale. I recommend shooting for a number under 60 with all of your food choices, to protect the health of your most important organ -- the brain -- as well as the rest of your body.

You'll be amazed how quickly cravings disappear!

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