Read an Excerpt
the Glycemic Load Diet Cookbook150 RECIPES TO HELP YOU LOSE WEIGHT AND REVERSE INSULIN RESISTANCE
By ROB THOMPSON DANA CARPENDER
McGraw-Hill, Inc.Copyright © 2009 Dana Carpender and Robert Thompson, M.D.
All right reserved.
Chapter OneHow the Glycemic-Load Diet Works
Before we get started, it will be helpful for you to know two definitions:
Glycemia: the presence of the sugar glucose in the blood
Glycemic: having to do with glucose in the blood
Unless you've been living under a rock, you've heard the term glycemic lately. A high-glycemic-load diet—a diet that raises blood sugar levels—is turning out to be correlated with most of the diseases we used to blame on fat intake: obesity, heart disease, female infertility, high blood fats, acne, insulin resistance and diabetes, even some cancers.
But what does it mean? What is the low-glycemic-load diet?
A low-glycemic-load diet (what I call simply the glycemic-load diet in this book for the sake of brevity) is an eating style that greatly lessens the amount of insulin your body has to make. It does this by preventing large amounts of glucose from rushing into your bloodstream all at once. Eliminating these "glucose shocks" not only helps you lose weight while continuing to enjoy satisfying amounts of good food but also can dramatically improve the way you feel and actually lengthen your life.
Before I explain this way of eating, let me give you a little background. Chances are you feel guilty about being overweight. You've been told all your life that it's just a matter of willpower, that it's all about "calories in, calories out," that all you have to do is eat less and exercise more and you'll lose weight and improve your health. If you're overweight, you must lack self-control. But is this true? Study after study has demonstrated that overweight people are no less disciplined than normal-weight people. No one can just dial down the number of calories he or she eats at will. We all know what the failure rate is for calorie-restricted diets. Chances are you've contributed to that statistic yourself.
Obesity results not from lack of willpower but from an imbalance in the body's hormones, substances that govern body chemistry. The best way to lose weight is to correct the underlying hormonal disturbances that caused you to gain weight in the first place. When people do that, they are often amazed at how easy it is to lose weight and keep it off. What went wrong to make you gain weight? It has to do with the way your body balances the energy you put into it versus the energy it expends.
How Your Body Uses Energy
What exactly is a calorie, anyway? A calorie is a measurement of energy. Just as we buy gasoline for our cars in gallons (or, outside the United States, in liters), we buy fuel for our bodies in calories. There are four sources of calories: protein, carbohydrate, fat, and alcohol. You may be surprised to hear that, despite all the low-fat propaganda, the biggest source of calories in the American diet by far is not fat but carbohydrate.
The main purpose of body fat is the same as the gas tank on your car: to let you carry a supply of fuel around with you to provide a steady source of energy between refuelings—in this case, between meals.
The idea behind fat-restricted diets was the belief that we literally "are what we eat"—that we get fat because we eat too much fat. If we cut dietary fat, we'd automatically eat fewer calories, and as a result we'd burn our own fat—the "fuel in the tank"—instead. The only problem is it didn't work. Twenty years of cutting fat have left Americans fatter, sicker, and more tired, not to mention with a spanking-fresh epidemic of type 2 diabetes. Why?
It turns out that there are several problems with the notion that a calorie is a calorie is a calorie: for one, we're not cars; we're complex living organisms. Unlike a car, which will run at the same rate right up to the moment when it sputters and dies for lack of fuel, your body has powerful mechanisms to balance the energy you take in with the energy you burn up. When you eat fewer calories, your body slows down. This is why low-calorie diets can make you tired—your body is trying to balance the fact that you're giving it less fuel by burning less fuel. Studies show that it is very possible for dieters' bodies to slow down so much that they won't lose weight—may even gain it—at 1,500 calories per day, which is clinically considered a semistarvation diet. The most discouraging thing about this diet-induced metabolic slowdown is that it doesn't just go away when you stop dieting. It persists for months. As a result, you actually gain weight eating fewer calories than you did before. That's right. Strict low-calories diets can actually make you gain weight.
A Tale of Two Fuels
Another difference between your body and a car is that your body is a dual-fuel machine. Your car can run on only one fuel, gasoline. But your body can run on two fuels: glucose ("blood sugar") and fat. Think about it. You've heard that you need carbohydrates for energy. You've also been told that this or that exercise will get you into your "fat-burning zone." The truth is, your body is happy to burn either fuel.
Again, the old saying "You are what you eat" is misleading. Your body can quickly turn carbs to fat and fat and protein to carbs. You don't need to eat fat to get fat, and you don't need to load up on carbs to keep your blood sugar up.
Here's the part you didn't know: your body has to get rid of glucose before it starts burning fat. All carbohydrates turn to glucose. If you give your body a serving of carbohydrates every few hours, your body doesn't bother to shift over to burning fat. If you have, say, cereal and juice for breakfast, a granola bar midmorning, a sandwich with a soda for lunch, pasta or a potato with dinner, and some chips in front of the television in the evening, your body can go through the whole day burning glucose instead of fat. If you have any glucose left over, your body will quickly turn it to fat and stash it on your belly, butt, or thighs.
So the question becomes "How can I get my body to burn fat instead of glucose?" The answer is simple and logical: stop giving your body all that glucose.
The Problem with Quick Energy
Maybe you have heard that carbohydrates give you "quick energy." It sounds good. But is it?
Gasoline is quick energy, so quick that if you checked your gas tank by match light you'd be lucky to survive the experience. That's why your car has fuel injectors—to turn quick energy into slow, constant energy, to feed just a tiny bit of that gasoline into the engine at a time. But your body doesn't have fuel injectors. It has no way to use carbohydrates gradually. High-carbohydrate meals simply didn't exist until mankind started farming grains and beans ten thousand years ago. That sounds like a long time, but in biological terms it really isn't. We come from hunter-gatherer ancestors who lived on meat, vegetables, and fruit in season, and our bodies are still made for that sort of diet, rather than for a diet based on grains and beans. Rapidly digestible, high-carbohydrate foods such as starch are a very recent addition to the human diet, and we simply don't have the mechanism to use big doses of it gradually.
When you eat a big dose of starch—say, a plate of spaghetti and a couple of slices of garlic bread—it all turns into glucose and floods into your bloodstream very quickly. Your blood sugar shoots up, and for the moment you feel satisfied. But high blood sugar is dangerous, and your body knows it. So it goes into action to get your blood sugar back down.
It's All About Insulin
How does your body get your blood sugar back down? It releases insulin. No doubt you've heard that insulin is that stuff that diabetics take. But what is it? What does it do?
Insulin is a hormone with a very specific task: it signals your body to take sugar out of your bloodstream, where it can cause trouble, and put it into your cells instead. It opens "doors" on the surface of your cells called insulin receptors. If you're using your muscles at that moment—walking, working out, whatever—your muscles will be able to burn some of that glucose. But if you're sitting at your desk, sitting in your car, sitting in front of the television, your muscle cells aren't going to be interested. So the insulin tells your body to convert the glucose into fat, opens the doors on your fat cells—and puts it in the tank for later.
Simply put, insulin is the fat storage hormone. So long as you have high levels of insulin in your bloodstream, your body will not only put fat into the tank; it will keep fat from going out of the tank. Insulin tells your body to store fuel, not tap into it.
The opposite occurs when your insulin levels fall. Your body gets the message that it doesn't have much glucose to run on and shifts over to burning fat for fuel instead. That's when your body starts to draw fuel out of the tank.
Think back for a moment to our hunter-gatherer ancestors, the ones who didn't eat grains and beans and therefore got only what little carbohydrate they found in wild vegetables and fruits, at least on a day-to-day basis. Most of the time, their bodies were running on fat from the game they ate. (Yes, much game is lean, but even in wild animals the organ meats, marrow, brain, and other internal tissues are rich in fat, and hunter-gatherers actually preferred these parts to the muscle meat.) When game was scarce, prehistoric humans could forestall starvation by eating vegetation. Although this was often largely indigestible carbohydrate such as grass, bark, roots, and unripe fruit, sometimes they found richer sources such as ripe fruit or even honey. Let's say they did get one big dose of carbohydrate—say they found a beehive and had a big party, eating all that honey. The honey would flood into their bloodstreams, their bodies would release insulin, and the glucose would be turned into fat and stored. No big deal. Because how often did they find a beehive? Soon they'd be back to eating game, their insulin levels would drop, and they'd shift right back to burning fat. In the meantime, the honey they ate would become fat, which they could use for fuel for a week or two. Simple and elegant.
The whole thing got messed up when we started to eat big doses of carbohydrate all the time. Indeed, modern humans consume hundreds of times more glucose in carbohydrates than their ancient ancestors did. By causing our bodies to constantly release insulin, we keep ourselves in fat storage mode. Our body takes all those calories and puts them into storage where we can't get at them, so we seem to be hungry all the time, even soon after we eat. Our muscles, organs, and appetite centers in our brain stay hungry, a state that has been called internal starvation. We eat plenty but never feel satisfied.
And It Gets Worse: Insulin Resistance and Type 2 Diabetes
For many of us, this constant oversue of our ability to turn glucose into fat for later turns really disastrous: our bodies stop responding to insulin, a condition called insulin resistance. Those "doors" on our cells, the insulin receptors, get harder and harder to open—think of them as having rusty hinges. It takes more and more and more insulin to open the doors and get the sugar out of our blood. Consequently, our insulin levels grow higher and higher, a condition called hyperinsulinemia. People with insulin resistance produce as much as six times the normal amounts of insulin, and that's the problem. Excessive insulin, whether given as medication or produced by the body, is notorious for causing weight gain. Indeed, most overweight people have insulin resistance.
These days, more people than ever have insulin resistance because we have become so sedentary. A hundred years ago, people weren't as susceptible as we are to obesity and diabetes because they were more physically active. All it takes is about thirty minutes of brisk walking to restore the body's sensitivity to insulin, but many of us don't even do that. We ride to work in a car or bus, sit at a desk all day, then come home and watch television. As we gain weight, exercise becomes more difficult, which contributes to insulin resistance as well. The less we use our muscles, the rustier the hinges on the doors get. As we slow down, our insulin resistance intensifies. However, the insulin receptors on our fat cells continue to work just fine long after the others start to fail. We can still store fat!
As insulin resistance progresses, our insulin levels rise as our bodies desperately try to open the doors on the cells and get the sugar out of our blood. Eventually, the poor overworked insulin-producing cells in the pancreas virtually burn themselves out, insulin production decreases, and we end up with high blood sugar all the time, which we call type 2 diabetes.
Stopping the Vicious Cycle
It's simple to stop the vicious cycle. Only two things are needed:
Drastically lower your glycemic load.
Do thirty minutes of moderate aerobic exercise—walking is just fine—four times a week.
Excessive amounts of insulin keep you hungry and encourage your body to store energy as fat. Reducing glycemic load works to promote weight loss by preventing insulin from rising to unnaturally high levels. Research studies have repeatedly shown that people who reduce the glycemic load of their diet without even trying to cut calories lose more weight than folks on low-fat diets who try to cut calories.
If you just lower your glycemic load and oil the hinges of your muscle cells with moderate exercise, you reverse your insulin resistance and the insulin levels in your blood drop like a rock. Your body stops socking away everything you eat into fat storage and starts acting like the dual-fuel machine it is, burning fat instead of glucose for most of your needs. Because you have enough fuel, you stop feeling hungry every second of every day.
As your energy levels increase, you'll find that exercise is not such an unpleasant idea. Healthy bodies that have enough fuel like to move—just watch the kids at the playground if you doubt it. You can start easy. Walking is as good an exercise as any for losing weight and increasing insulin sensitivity. It takes only thirty minutes to open those doors on your cells. Or maybe you'd like to bike to the store, or putter around the garden, or even dance. The Russians have a wonderful phrase for it: muscular joy.
You'll be able to actually enjoy using your body again.
Glycemic Index Versus Glycemic Load
You hear the word glycemic all the time these days. Magazines recommend a "low glycemic diet," often suggesting that such a diet should be high in fruits, vegetables, and whole grains (the fruit and vegetables are OK, but the "whole grain" is wrongheaded, as we'll get to in a moment.) Ads for prepackaged diet club meals claim that they've used the "secret of the glycemic index" so that "carbs are no longer off limits."
The problem is that magazine and television ads are unclear as to the difference between glycemic index and glycemic load. Trust me. There's a big difference, and not understanding it can ruin your efforts to lose weight. So let's clarify the two terms.
We'll start with glycemic index, the older concept. This is a measure of how quickly any given carbohydrate food is absorbed into the bloodstream, which in turn governs how high blood sugar will rise as a result.
How is glycemic index determined? A group of people has their fasting blood sugar tested and recorded. They then eat a portion of the food to be tested. That portion is calculated carefully to contain fifty grams of carbohydrate available for absorption into the bloodstream—keep this point in mind, because we'll come back to it. The subjects' blood sugar is then tested at regular intervals to see how sharply it rises and falls. These results, which can vary from person to person, are then averaged out.
That average is then ranked against a "reference food"—usually pure sugar or white bread. The reference food is rated 100, and other foods are given a number indicating how they affect blood sugar in comparison to it. For example, using white bread as reference food, oranges have a glycemic index of 60, which means fifty grams of available carbohydrate in an orange will raise blood sugar 60 percent as much as fifty grams of available carbohydrate in white bread will. Even though the amount of glucose that ultimately enters your body is the same, when it is consumed in the form of an orange it raises your blood sugar less than when it is delivered in the form of white bread.
Glycemic-index tests have turned up some surprising results. For instance, in the 1970s a push started to get us to eat more starches: bread, potatoes, cereal, pasta, rice, and the like. It was believed that starches were absorbed more slowly than sugar—and that a starch-heavy diet would, therefore, lead to stable blood sugar levels and reduce hunger. The glycemic-index measurements proved this to be wrong.
Excerpted from the Glycemic Load Diet Cookbook by ROB THOMPSON DANA CARPENDER Copyright © 2009 by Dana Carpender and Robert Thompson, M.D.. Excerpted by permission of McGraw-Hill, Inc.. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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