Your Brain Likes Some Carbs – Fast Carbs and Slow Carbs

Your Brain Likes Some Carbs

One of the great contributions to understanding the impact of food on blood sugar and insulin levels is the recent dis­covery that carbohydrates—sweets and starches—have widely varying and surprisingly unpredictable effects on blood sugar. This is causing a revolution in the way we judge carbohydrates and their potential influence on health in general and mental health in particular.

For the most part, your brain needs steady supplies of glucose supplied by foods that slowly raise blood sugar lev­els. However, sometimes your brain needs a jolt of glucose to arouse it to its greatest heights. It’s interesting that our evolutionary diet was not devoid of such quick sugar boosts. For example, dates, one of our oldest foods—once ironically recommended for diabetics—send blood sugar soaring far more than eating plain refined sugar, candy, or practically any other food.

Best advice: You can and should eat carbohydrates com­patible with the type diet your brain best thrives on. It’s a matter of knowing which foods those are.

Fast Carbs and Slow Carbs

What is the right stuff to keep your blood sugar optimal and your brain functioning at peak power? Which carbo­hydrates best sustain blood sugar reservoirs needed by the brain for energy? The answer is of major relevance for brain function, considering the brain is totally dependent on the status of glucose in your blood.

Essentially, you can judge carbohydrates by whether they cause rapid, steep increases in blood sugar or slow, gradual rises, or something in between. Until recently, sugar was deemed the worst villain. For years, scientific dogma held that eating plain sugar zipped right through the digestive tract, causing the most rapid and highest ele­vations of blood glucose. Conversely, starches, like bread and potatoes, were thought to dawdle in the intestinal tract, leisurely raising blood sugar. That’s why sugar was consid­ered anathema for diabetics, but starches okay. It was a seismic scientific shock to learn this long-time belief was a monumental myth.

“Eating white potatoes or white bread is just like eat­ing candy, as far as your body knows.” —Walter Wil­lett, chairman of nutrition, Harvard School of Public Health

No question, carbohydrates differ in their powers to raise blood sugar. But it’s far more complicated than the notion that simple sugars are “fast” and starches are “slow.” New research, beginning in the 1980s, has created a radical new view of how carbohydrates regulate blood sugar. The new scientific truth: Each food has its own distinctive abilities to raise blood sugar. And scientists can accurately predict the sugar-raising properties of a food only by test­ing it. They are often quite surprised to find that a fruit, such as dates, causes blood sugar to spike rapidly, while a similar food—dried apricots—does not.

By feeding numerous people carbohydrates and metic­ulously measuring their blood sugar increases, pioneering researchers have identified each food’s unique glucose-boosting potential. Among the startling revelations: White potatoes raise blood glucose faster than plain sugar does; white bread, more quickly than ice cream. This has turned conventional scientific wisdom on its head, forcing a com­plete re-examination of which foods over the long run are best for the brain, arteries, and general health.

Important new stuff: Technically, carbohydrates that quickly raise blood sugar are called “high glycemic index” or high GI foods—glycemic being another term for sugar. High GI foods can produce spikes and valleys in blood sugar, sometimes creating a feast or famine for the brain. In contrast, carbohydrates that gradually raise glucose are “low glycemic index” or low GI foods. Generally, eating low GI foods discourages sharp peaks and valleys in blood sugar, creating more mental equanimity. Such “slow” carbs also help ward off and reverse insulin resistance with its hazard of memory impairment.

For the first time in human history, because of modern food processing, our diet is centered on huge quantities of high glycemic carbohydrates, refined sugars and starches, that require the pancreatic production of large amounts of insulin day after day for a lifetime. Small wonder, many bodies are not genetically able to meet the demands and develop insulin resistance and Type 2 diabetes. Such dis­turbances in blood sugar and insulin levels are hazardous to your body and your brain.

The Hazards of “Fast” Carbohydrates

Harvard researchers have found that a diet rich in quickly digested high glycemic index carbohydrates, that swiftly raise blood sugar, doubles or triples your odds of develop­ing diabetes, insulin resistance, and heart disease.

Eating high glycemic index foods frustrates your ability to lose weight, promoting obesity, and Type 2 diabetes. Low GI foods suppress appetite and stimulate the burning of body fat, say Australian researchers. Several weight-loss diets are based on eating low GI foods.

A high glycemic index diet depresses good-type HDL cholesterol, according to a British study of 1400 middle-aged adults. The best dietary way to raise HDLs, they found, was to eat a low glycemic index diet. Possible explanation: A low glycemic diet increases sensitivity to insulin which raises HDLs.

High glycemic index foods lead to “insulin resistance,” or “prediabetes” in which insulin becomes ineffective, pro­moting high blood pressure, clogged arteries, heart attacks, strokes, possibly even Alzheimer’s disease, according to research. Eating a low GI diet for only a few weeks has reversed “insulin resistance” in both heart bypass patients and young women.

Persistent high blood sugar from eating a high glycemic index diet can also threaten the brain directly by inflicting a form of age-related damage known as “glycation.”

The solution to this modern dilemma is to eat carbohy­drates that best, nourish the brain by keeping blood sugar and insulin levels essentially “normal” and that are consistent with the long-ago diets that formed our brains. That means basing your diet on carbohydrates with a low glycemic index rather than a high glycemic index—foods that cause slow rises rather that rapid spurts in blood sugar and insulin. To do that, you must have accurate informa­tion on the glycemic indexes of common foods.

BOTTOM LINE: It’s important to know which carbo­hydrates spike blood sugar so you can maintain opti­mal blood glucose levels required to fuel your brain and to stave off potential brain damage.

The Incredible Carrot Myth and Other Facts

Unhappily, some of the information on the glycemic index values of foods in popular distribution is wildly wrong. Some of the first analyses done in the early 1980s are still being quoted as gospel, even though they are out of date, erroneous, and have been replaced in the scientific arena with findings from newer analyses. A case in point: the car­rot.

Because of the tenacity of misinformation, millions of Americans on a supposedly low glycemic index diet (some diabetic, some trying to lose weight, suppress hunger, or gain energy per The Zone) are told to shun carrots like the plague; supposedly, carrots send blood sugar levels soar­ing. Not so. The truth is carrots are actually a low glycemic index food, according to the most recent authoritative tests published in 1999 by the world’s leading experts in Aus­tralia and Canada. The fact is carrots contain so few car­bohydrates (only 5 to 7 percent or a mere 3 grams in half a cup) that to spike blood sugar you would have to eat at least one and a half pounds or five cups at one sitting.

BOTTOM LINE: Raw, cooked, or canned, carrots are good for your blood sugar and your brain. They do not cause blood sugar surges! Widespread reports that car­rots are detrimental to the blood sugar of diabetics, peo­ple trying to lose weight, or anyone, for that matter, are “simply wrong,” says world authority Dr. Jennie Brand-Miller, at the University of Sydney in Australia, who continually conducts analyses of the glycemic index of foods.