Atkins Diabetes Revolution (28 page)

To solve the problem of misleading GI numbers, researchers have come up with a number that’s even more valuable: the glycemic load (GL).
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The GL numbers are more realistic because they take into account the fiber content and portion size of a food. To calculate the GL of a food, take the GI ranking and multiply it by the number of grams of carbohydrate per serving, and then divide that number by100. Using this calculation, the GL of that baked potato would be about 38.

The GL is a measure of the quantity of carbs in a typical portion, which makes it a very useful tool for deciding which carbs to eat.How- ever, the portion sizes used to determine the GL are small, so it’s easy to eat more and have your carbs add up faster than you realize. Even when you’re eating high-quality carbs, you still need to keep an eye on your total carb intake.

USING THE ATKINS GLYCEMIC RANKING

How can you choose the right carbs for you, in the right amounts, without juggling a calculator, a measuring cup, and a carb counter? By using the Atkins Glycemic Ranking. This is a three-tier system that Dr. Atkins and nutritionists working with him developed for ranking foods, based on a combination of their glycemic index, glycemic load, and Net Carbs. This easy-to-follow guide is very helpful when counseling patients about their carbohydrate choices, and we believe you, too, will find it helpful (see Appendix 4, page 467).

The Atkins Glycemic Ranking sorts carbohydrate-containing foods into three categories:

1. Low AGR: eat regularly
   
2. Medium AGR: eat in moderation
   
3. High AGR: eat sparingly
   

Remember that the AGR ranking is based on a food’s impact on your blood sugar, not on how many carbs it has, so it’s still crucial to keep an eye on portion size and count your daily carbs. A food such as lentils can have a low AGR per serving, but each half-cup serving still packs about 12 grams of Net Carbs. On the other hand, a low-AGR food, such as broccoli, is very low in carbs and, because it’s relatively high in fiber, it’s ranked zero on the GI and GL scales.

When you combine the AGR charts that start on page 467 with your carb gram counter, you have the necessary tools for choosing the foods and portion sizes that will help control your blood sugar. As you’ll see from the charts, you’re not in danger of going hungry or getting bored by your food even if you stick to nothing but the low-AGR foods. And remember, to slow the entry of glucose from any carbohydrate food, even the low-AGR ones, eat them as part of meals and snacks that also contain fat and protein.

By using the AGR categories to choose your carbs, you’ll be well on your way to weight loss. More important, you’ll be traveling down the road to stable blood sugar, better blood lipids, and a reduced risk of heart disease.

“I’M STILL HUNGRY”: THE HIGH-GI DIET

Almost by definition, a high-GI diet will cause obesity because of its major effect on appetite. Here’s why: When you eat foods that have a high-GI ranking, your blood sugar shoots up. That makes your pancreas pour out insulin to clear away the extra blood sugar; at the same time, your body suppresses the hormone glucagon, whose role it is to counteract a drop in blood sugar. For several hours after the high-GI meal, then, you end up with high levels of insulin and low levels of glucagon. That makes your blood sugar drop too low, which means you get hungry, crave more high-GI carbs, end up eating too much— and start the whole cycle all over again.

RESEARCH REPORT: HEART DISEASE, GI, AND GL Researchers have known for years that a diet high in refined carbohydrates can raise your triglycerides—a risk for heart disease. More recently,they’ve come to realize that a diet high in refined carbohydrates is also a diet that has a high overall glycemic index. Several studies have looked at how a high-GI diet relates to heart disease. Not surprisingly, there’s a strong connection. In a 2000 report that looked at results from the Nurses’Health Study,the women whose diets were made up of foods with the highest glycemic load had the highest risk of heart disease. These women had almost double the risk of heart disease as the women whose diets had the lowest glycemic load. The heaviest women in the study had the highest risk, but they didn’t have to be overweight for their risk to go up. The increased odds of heart disease from a high- glycemic load diet started at BMIs of just 23.
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Another study in 2001, based on data from the Third National Health and Nutrition Examination Survey, looked at the relationship between the glycemic index and levels of HDL cholesterol in the blood. Nearly 14,000 people participated in that study, and sure enough, the ones whose diets were highest in high-GI foods also had the lowest HDL levels.
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(A reminder: HDL cholesterol is known as the “good” cholesterol,so lower levels are more dangerous to your heart health.)

As you already know, the combination of low HDL cholesterol and high triglycerides signals the metabolic syndrome. In a 2001 study of nearly 300 women, researchers found that the women whose diets were made up of foods with the highest glycemic load also had the lowest HDL and the highest triglycerides compared with the women whose diets were made up of foods with the lowest glycemic loads. The triglyceride difference was particularly notable among the heavier women who ate high-GL diets—their mean triglyceride level was 198,above the recommended level of 150. The researchers concluded that a high-GL diet is a potential risk factor for heart disease, particularly in women who are prone to insulin resistance.
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Once again,it is gratifying to see research catch up to Dr.Atkins’clinical observations. Perhaps this means that we will soon see the national nutritional guidelines recognize the importance of controlling the quality and quantity of carbohydrate intake. But there is no need for you to wait for them:You can take action right now.

WHY ARE AMERICANS OBESE?

If you follow the standard advice to control your fat intake rather than your carbs, you’re likely to end up as a statistic in the worldwide obesity epidemic—if you’re not there already. By replacing the fat in your diet with carbohydrates high on the glycemic index, you’ve unwittingly fallen into the obesity trap. The very same low-fat carbohydrate foods your doctor suggests you eat—potatoes, pasta, bread, rice—are exactly the foods that are high on the glycemic index. That makes them the foods that are most likely to make you hungry and cause you to overeat! Take at look at the following table from the Nurses’ Health Study from 1984. It lists the 20 most commonly eaten carbohydrates in the United States, along with their glycemic ranking and glycemic load. Could there be a better illustration of why waistlines today are so large? Almost all these foods are high in carbohydrates, high on the GI and GL rankings, and low in overall nutrition.

TWENTY MOST COMMON CARBOHYDRATE-CONTAINING FOODS

Study after study since the late 1970s has shown that eating a low- GI diet increases satiety, decreases hunger, and lowers the amount of food eaten. Here’s one good example: A study of obese teenage boys published in 1999 looked at the effect of eating meals containing different GI levels but the same number of calories. The teens ate the meals for breakfast and lunch; then they were followed for five hours to see how soon they got hungry again and asked for snacks.When the boys ate the high-GI meals,they were hungry again in well under three hours—and ate snacks that provided a lot of calories.After the low-GI meals, they weren’t hungry again until nearly four hours later—and they ate 81 percent fewer calories from snacks.
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This response to a low-GI diet might seem familiar. It’s exactly what happens when you start following the ABSCP, which by definition is a low-GI way of eating. It’s pretty clear that controlling your carbs increases satiety, reduces hunger, and improves your overall nutrition.When you choose low-GI, low-AGR foods, you’re eating fewer carbs overall. The carbs you do eat are high-quality, low-GI carbohydrates from fresh vegetables, fruits, and relatively unprocessed foods—and they’re part of a meal that contains protein and healthy fats.You fill up fast and stay full longer—and you get lots of vitamins, minerals, and other valuable nutrients in these foods.

DIABETES AND THE HIGH-GI DIET

It seems pretty obvious that if foods high on the glycemic index are a big part of your diet, your risk of getting diabetes goes up. Cut back on the high-GI foods and you’ll probably lose weight, improve your insulin re-sistance and blood lipids, and lower some other markers for heart disease and diabetes.That could go a long way to preventing diabetes.

What if you already have diabetes? In that case, getting away from a high-GI diet is no longer an option—it’s a necessity.A very important 1999 study makes the point clearly. The study looked at how two identical diets with different GIs affected people with Type 2 diabetes. The 20 patients in the study were randomly assigned to eat preweighed diets with different GIs—one high,one low—for 24 days.After the 24- day period, they then switched to the other diet. Each diet was exactly the same in terms of protein, fat, carbohydrates, and dietary fiber. The study was designed simply to change the types of foods eaten, not to cause any change in the participants’ weight. The different GI levels came from the way the starchy foods were prepared.

When the patients ate the low-GI diet, their blood sugar numbers averaged 30 percent less. On both diets, LDL cholesterol dropped significantly, but it dropped a lot more on the low-GI diet. Perhaps even more important than the drop in blood sugar and LDL cholesterol was the change in plasminogen activator inhibitor-1 (PAI-1) activity. High PAI-1 levels mean that your blood is more likely to clot and cause a heart attack—and people with diabetes tend to have dangerously high PAI-1 levels. On the low-GI diet, PAI-1 was normalized; on the high-GI diet, it stayed the same.
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We could go on a lot longer about all the studies that show how effective a low-GI diet is in controlling diabetes,but we think you get the idea. So do health authorities around the world. The GI concept is now widely used internationally as the basis for healthy eating recommendations for people both with and without diabetes.

There’s one major exception: the United States. The American Diabetes Association (ADA) and other organizations still don’t think there’s enough scientific evidence in favor of the glycemic index concept. Instead, they focus on the total amount of carbohydrate (and calories) in the diet, not the type of carbs or where they come from, and they recommend that you get 55 percent of your calories from carbohydrates. They also appear to think the GI approach is too complicated for the average person to understand. That’s why the exchange system recommended by the ADA (which itself is complicated) includes all sorts of high-GI foods made from refined carbohydrates—and that’s why it doesn’t help most of the people who follow it. But we think you’re intelligent enough to grasp this concept. Using the Atkins Glycemic Ranking to choose your carbs is simple and effective. We hope you’ll stick to it as you follow the dietary recommendations in the next five chapters.

TEST YOUR GLYCEMIC KNOW-HOW

How well do you understand the AGR rankings? Can you pick the food with a lower AGR?