Blood sugar is not a bad guy. This sweet stuff is your body’s best friend—rocket fuel for hardworking muscles and brain cells, energy that (like extra flashlight batteries or the nation’s strategic oil reserves) can be stored and then released at precisely the moment you need it most.
It’s only when levels rise too high—or sink too low—that blood sugar has serious, negative consequences for your mood, your weight, your energy level, your health, and even your life. The trick to staying on blood sugar’s good side is simple: Work with—not against—the intricate and intelligent biochemical system that keeps levels within a healthy range. Your first step? Understand how your blood sugar control system works by reading this brief owner’s manual.
Nearly all of the blood sugar that powers your cells comes from the carbs on your plate—the fruits, veggies, grains, and sugar that your digestive system converts into the tiniest of sugar molecules: glucose.
In a sense, carbs are like candy. Whether you’re eating corn chips, chocolate mousse, or broccoli spears, carbohydrate foods all contain chains of sugar molecules. Some chains are short. Others are long. Some, like the sugars glucose and fructose, need almost no digestion before they can be absorbed into your bloodstream. Others, like the fiber in oatmeal, are so tough that your body cannot break them down.
The moment you slide a forkful of apple pie or mashed potatoes into your mouth, a series of enzymes begins breaking apart these chains. Ultimately, all carbs are converted into glucose, fructose, or galactose—tiny sugar molecules that slide easily through your intestinal wall and into the bloodstream. There’s one more stop before this new supply of blood sugar can reach hungry cells: the liver. Here, cells hold on to some glucose for later use (it’s stored in a form called glycogen). And fructose and galactose are converted to glucose. Like gasoline pumped into the tank of your car at the start of a summer road trip, the glucose that circulates in your bloodstream is now ready to power your mind, muscles, and metabolism.
Until recently, nutrition experts thought complex carbs—starches comprised of long chains of sugar molecules—were the “good” carbs that kept blood sugar low and steady. “Bad” carbs were simple sugars, with short chains that were absorbed quickly. But that’s old think. Experts now know that some simple carbs are absorbed slowly, while some complex carbs convert swiftly into blood sugar.
A better ranking system: the glycemic index, which rates a food’s effect on your blood sugar based on lab tests, not conjecture. This system is one of the foundations of the Sugar Solution plan, and you’ll be hearing about it throughout this book.
Not all carbs are created equal. Some reach the finish line faster than others—and when it comes to healthy blood sugar, bet on the tortoise, not the hare.
High-glycemic carbs, such as white rice and white bread, are broken down and absorbed swiftly, raising blood sugar fast. Low-glycemic carbs move through your digestive system slowly and release sugar into your bloodstream slowly. Many factors influence how rapidly or slowly a carb becomes blood sugar. Among them: whether you’ve also consumed something acidic (like vinaigrette dressing) or fatty (like butter on bread), both of which slow absorption; whether the starch in the food has been thoroughly cooked (the longer you cook a starch, the faster it’s absorbed by your body); whether the carb is surrounded by a tough coating such as the covering on beans and seeds, which slows absorption; how finely a carb such as flour has been ground (finer grains absorb faster); and whether a carb comes with digestion-slowing viscous fiber (as do oatmeal and lentils).
Muscle cells and the tissues of organs throughout your body rely on glucose for energy to function. Walking, breathing, sweating, digesting, producing new cells, growing a baby during pregnancy, and thousands of tiny intercellular functions are all driven by this teeny-tiny sugar.
Your body’s top glucose hogs are your brain and nervous system, which collectively consume about half the glucose that circulates in your bloodstream. Even at rest, the brain devours a greater percentage of your glucose supply than your body uses while active.
It takes just 7 ounces of pure glucose—less than 1 cup—to fuel the daily work and play of your cells. Like a thrifty Boy Scout, your body’s glucose abides by the motto “Be prepared.” About 40 percent of the glucose released after a meal is stored in the liver and muscles in a form called glycogen. When blood sugar falls between meals or food isn’t available, the liver releases its supply into the bloodstream as glucose. Muscle cells also hoard glycogen for their own private use. (And when your body runs out of glycogen, fat cells release fatty acids for use by skeletal muscles, your heart, and other tissues.)
Your glucose reserves must be replenished daily. Your body keeps only about 1,900 calories’ worth of glycogen in its larder—enough to sustain you for about 16 hours. When that runs low, it burns fat and even uses protein to create more glucose. Most Americans have more than enough, however, thanks to overeating, inactivity, and a taste for refined carbohydrates. When there’s an overload of glucose, your liver and muscle cells can run out of storage space. The excess sugar is stored—as fat.
But if you exercise (the Sugar Solution plan recommends at least 30 minutes at least five times a week), you not only burn more glucose, you also activate a mechanism that pulls blood sugar into cells that’s independent of insulin. You get a double benefit: no excess insulin, lower glucose.
Normal blood sugar stays within a range of 60 to 90 milligrams of glucose per deciliter of blood (mg/dl) before a meal and rises to between 120 and 160 mg/dl after eating. Experts admire the body’s ability to maintain this precise, narrow range around the clock and suspect its main purpose is to keep sugar supplies to the brain steady. (Brain cells can store only the smallest amount of extra glucose and cannot use fatty acids for power; they must constantly “sip” from the bloodstream.)
If blood sugar control is a balancing act, hormones act as the tightrope walker’s pole. “Blood sugar regulation involves a balance between hormones that raise blood glucose and those that lower it,” says Robert Cohen, MD, professor of medicine in the division of endocrinology and metabolism in the department of medicine at the University of Cincinnati and director of the diabetes clinic at University Hospital in Cincinnati. The key players: insulin, which lowers blood sugar by persuading cells to absorb it; and glucagon, which tells the liver to release stored glucose.
Insulin is produced by beta cells in the pancreas. Under healthy conditions, these clever cells sense glucose levels in the bloodstream and adjust their insulin output accordingly. After you eat, insulin levels rise. Once released, insulin ushers glucose out of the bloodstream and into waiting cells throughout the body. When sugar levels fall, so does insulin production.
But if you’re overweight and inactive, receptors on muscle, liver, and organ cells throughout your body may grow deaf to insulin’s signals. Then, your beta cells pump out extra insulin, raising your risk for stubborn overweight as well as health problems. Over time, overeating fatty and sugary foods may prompt your beta cells to lose their smart ability to sense changes in blood sugar levels. They stop producing the right amount at the right time. Blood sugar levels rise dangerously.
If you haven’t eaten in a while, alpha cells in the pancreas send glucagon into the blood. This hormone raises blood sugar by signaling the liver to give up its glycogen stores. Glycogen becomes blood sugar, ready to feed your body’s fuel-hungry cells. If you overeat foods that raise blood sugar dramatically, this system can stay turned on and prevent your body from burning a secondary fuel: fatty acids stored in fat cells. This is a problem if you’re trying to lose weight.
Meanwhile, chronic stress can keep another blood sugar backup plan switched on for too long. If you need a sudden burst of energy—to outrun a charging saber-toothed tiger, for example—your adrenal glands churn out stress hormones including epinephrine and cortisol, which tell your body to release and burn stored glucose. That worked well for cavemen and cavewomen, who faced short-term stresses like marauding cats. As you’ll discover later in this book, 21st-century chronic stress can keep these hormones raging, leaving you with higher blood sugar around the clock. Chronic stress can also prompt you to overeat and store extra fat in your belly … which leads to more insulin resistance. Stress reduction isn’t a luxury; it’s a necessity for maintaining a healthy weight!
Alice McColgin controls her blood sugar the natural way: with diet and exercise.
A few years ago, McColgin, a 53-year-old account manager in Indianapolis, didn’t feel well. She was extremely tired and thirsty, her vision was blurry, and she had to take frequent bathroom breaks. She got cold sweats, too. When she came down with a severe urinary tract infection, she went to her doctor, who tested her blood sugar. “Turned out my blood sugar was over 400,” says McColgin. “I had become heavier and more inactive than ever and was paying the price.”
To reduce her blood sugar quickly, her doctor prescribed a pill that makes cells more sensitive to insulin. But McColgin was determined not to become dependent on the medication and took matters into her own hands. She began walking for 10 to 15 minutes, four or five times a week. “My doctor was impressed with how much I had reduced my blood sugar in 6 weeks,” she says. “From then on, with the encouragement of my family and friends, exercise became a part of my routine.”
McColgin is careful to steer clear of refined sugars, and she watches her calorie and fat intake. To avoid temptation, she says, “I tell myself there are so many things I want to do, and eating the sugar will probably shorten my life.”
Today, McColgin has built up to 50 to 55 minutes of aerobic exercise—walking, stationary cycling, or using a NordicTrack—4 or 5 days per week, and she’s lost more than 30 pounds. She was weaned down and finally taken off the medication completely. “I have more energy, I sleep better, and I think more clearly,” she says.
Eventually, almost everyone with type 2 diabetes needs medication to help control blood sugar. But losing weight, exercising, and eating well can help delay that inevitability, safeguard your health, and yield benefits no drug can achieve: You’ll feel great, look great, and have the satisfaction of knowing you’re in control of your health.